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RE: [PrimeNumbers] Isomorphic Numbers

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  • Jon Perry
    Using: { test(n,k)= v=vector(k,i,i+n-1); vl=length(v);fl=0;pc=0; for (i=1,vl-1,for (j=i+1,vl, if (isprime(v[i]+v[j])!=isprime(v[i]*v[j]+1),fl=1;break); if
    Message 1 of 26 , Mar 4, 2003
      Using:

      {
      test(n,k)=
      v=vector(k,i,i+n-1);
      vl=length(v);fl=0;pc=0;
      for (i=1,vl-1,for (j=i+1,vl,
      if (isprime(v[i]+v[j])!=isprime(v[i]*v[j]+1),fl=1;break);
      if (fl==1,break);
      if (isprime(v[i]+v[j]),pc++)));
      [fl,pc];
      }

      to check the current list yields 0 primes for all run length>7.

      So I think we should adopt a policy of a least 1 prime from a range.

      Jon Perry
      perry@...
      http://www.users.globalnet.co.uk/~perry/maths/
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    • Jon Perry
      The first with rl 8 is [5255:2] [9312:1] is the only other to 10000. Jon Perry perry@globalnet.co.uk http://www.users.globalnet.co.uk/~perry/maths/
      Message 2 of 26 , Mar 4, 2003
        The first with rl 8 is

        [5255:2]

        [9312:1] is the only other to 10000.

        Jon Perry
        perry@...
        http://www.users.globalnet.co.uk/~perry/maths/
        http://www.users.globalnet.co.uk/~perry/DIVMenu/
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        http://www.brainbench.com

        -
      • Phil Carmody
        ... It correctly gave me the length 5 and 6 results, so I applied the strong law of small numbers, which I double-checked using engineers induction. That s
        Message 3 of 26 , Mar 4, 2003
          --- Jack Brennen <jack@...> wrote:
          > Phil, I think there is a problem with your sets of numbers... you don't
          > seem to have considered the case where a & b are both even, thus
          > requiring that ab+1 be an odd composite.

          It correctly gave me the length 5 and 6 results, so I applied the strong law
          of small numbers, which I double-checked using engineers' induction.

          That's what caveats are for, I guess.

          I shut down my emacs/shell/GP window, so I have no way of working out where
          I went wrong, it was all ephemeral.

          Phil


          =====
          "Only an admission that he does possess weapons of mass destruction
          would do, sources said: 'The rest is just gesture politics." -- Hoon

          "Are you still bombing your wife?" -- Winjer

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        • jbrennen <jack@brennen.net>
          ... In that case: run length 8 - (5255..5262) run length 9 - (8009..8017) run length 10 - (16268..16277) run length 11 - (16268..16278) run length 12 -
          Message 4 of 26 , Mar 4, 2003
            --- In primenumbers@yahoogroups.com, "Jon Perry" <perry@g...> wrote:
            >
            > So I think we should adopt a policy of a least 1 prime from a range.
            >

            In that case:

            run length 8 -> (5255..5262)
            run length 9 -> (8009..8017)
            run length 10 -> (16268..16277)
            run length 11 -> (16268..16278)
            run length 12 -> (118151..118162)
            run length 13 -> (252035..252047)
            run length 14 -> (267485..267498)
            run length 15 -> (267485..267499)
            run length 16 -> (305923..305938)

            With no length 17 run less than 5*10^6.
          • Jon Perry
            Another challenge is to find to max. number of primes. rl8; ? for (n=10000,50000,x=test(n,8);if (!x[1] && x[2] 0,print1(n : x[2] , ))) 12106:2, 12775:2,
            Message 5 of 26 , Mar 4, 2003
              Another challenge is to find to max. number of primes.

              rl8;
              ? for (n=10000,50000,x=test(n,8);if (!x[1] && x[2]>0,print1(n":"x[2]", ")))
              12106:2, 12775:2, 13069:2, 15869:3, 15870:3, 16064:1, 16189:2, 16268:1,
              17409:1,
              17920:2, 17924:2, 18344:5, 18411:2, 18416:1, 18552:1, 19466:1, 21715:2,
              21806:1
              , 22820:1, 24689:1, 25956:1, 26113:2, 26865:1, 27304:3, 28479:3, 28480:2,
              28481:
              1, 29709:1, 29931:1, 31614:1, 31725:1, 34035:1, 34410:1, 34805:1, 35091:1,
              35359
              :2, 36204:1, 36205:2, 36633:2, 36634:3, 36716:1, 36784:2, 37520:1, 38829:1,
              3924
              7:2, 39296:1, 39759:1, 39760:2, 39935:2, 40403:3, 40404:3, 40748:1, 42866:1,
              434
              05:2, 43829:1, 45192:1, 46362:1, 47678:1, 48019:3, 48315:1, 49484:1,
              49755:1, 49
              789:2, 49790:1, 49953:1,

              So 18344:5 is the current record.

              Jon Perry
              perry@...
              http://www.users.globalnet.co.uk/~perry/maths/
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            • Phil Carmody
              ... 2420+2420 = 4840 = composite 2420*2420+1=5856401 = prime Are the two elements supposed to be distinct? Jon doesn t state that in his frist post today. Phil
              Message 6 of 26 , Mar 4, 2003
                --- Jack Brennen <jack@...> wrote:
                > run length 10 -> (2419..2428)

                2420+2420 = 4840 = composite
                2420*2420+1=5856401 = prime

                Are the two elements supposed to be distinct? Jon doesn't state
                that in his frist post today.

                Phil


                =====
                "Only an admission that he does possess weapons of mass destruction
                would do, sources said: 'The rest is just gesture politics." -- Hoon

                "Are you still bombing your wife?" -- Winjer

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              • Phil Carmody
                ... I agree with you on all previous data points, and this one too:
                Message 7 of 26 , Mar 4, 2003
                  --- "jbrennen <jack@...>" <jack@...> wrote:
                  > --- In primenumbers@yahoogroups.com, Jack Brennen <jack@b...> wrote:
                  > >
                  > > There is no run of length 21 below 10^7 (again, subject to the
                  > > caveat of only using a probable prime test).
                  > >
                  >
                  > run length 21 -> (15776479..15776499)

                  I agree with you on all previous data points, and this one too:
                  <<<
                  Starting program: /mnt/net/kilospaz/home/phil/projects/maths/primes/conjectures/perry/sumprod 1 21
                  [...]
                  t=60.450000 b=15728652)

                  Breakpoint 4, main (argc=3, argv=0x0) at sumprod.c:108
                  (gdb) next
                  (gdb)
                  (gdb)
                  15776479..15776499 is len 21
                  >>>

                  > No run of length 22 below 2.8*10^7.
                  >
                  > I'll let it run for a day or so before stopping the search.
                  > It's currently extending the search limit by about 14000/second.

                  The "t=60.45" means the program took 60.45 seconds of 900MHz Duron.
                  I'm currently clocking 200000/s, but expect to slow down as time goes on.

                  <<<
                  t=89.730000 b=37748755)

                  Breakpoint 4, main (argc=3, argv=0x0) at sumprod.c:108
                  (gdb) next
                  (gdb)
                  (gdb)
                  38392415..38392436 is len 22
                  >>>

                  90s, but that run didn't start from 0, but from the len=21 one.

                  So I'm looking at the 23 now, hopefully I'll be able to finish my sentence
                  before it find one...

                  ..., bleh.

                  Phil


                  =====
                  "Only an admission that he does possess weapons of mass destruction
                  would do, sources said: 'The rest is just gesture politics." -- Hoon

                  "Are you still bombing your wife?" -- Winjer

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                • Phil Carmody
                  ... unbleh!
                  Message 8 of 26 , Mar 4, 2003
                    --- Phil Carmody <thefatphil@...> wrote:
                    > <<<
                    > t=89.730000 b=37748755)
                    >
                    > Breakpoint 4, main (argc=3, argv=0x0) at sumprod.c:108
                    > (gdb) next
                    > (gdb)
                    > (gdb)
                    > 38392415..38392436 is len 22
                    > >>>
                    >
                    > 90s, but that run didn't start from 0, but from the len=21 one.
                    >
                    > So I'm looking at the 23 now, hopefully I'll be able to finish my sentence
                    > before it find one...
                    >
                    > ..., bleh.

                    unbleh!

                    <<<
                    t=156.960000 b=75497473)

                    Breakpoint 4, main (argc=3, argv=0x0) at sumprod.c:108
                    (gdb) next
                    (gdb)
                    (gdb)
                    76350646..76350668 is len 23
                    >>>

                    and instantly thereafter:
                    76350646..76350669 is len 24

                    Phil


                    =====
                    "Only an admission that he does possess weapons of mass destruction
                    would do, sources said: 'The rest is just gesture politics." -- Hoon

                    "Are you still bombing your wife?" -- Winjer

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                  • Phil Carmody
                    ... 370902159..370902183 is len 25 (1262 seconds, FWIW) I ll not look at the must include a prime version until I ve got to 2^31 and my signed ints run out
                    Message 9 of 26 , Mar 4, 2003
                      > 38392415..38392436 is len 22
                      > 76350646..76350668 is len 23
                      > 76350646..76350669 is len 24

                      370902159..370902183 is len 25

                      (1262 seconds, FWIW)

                      I'll not look at the 'must include a prime' version until I've got to 2^31
                      and my signed ints run out of juice.

                      Phil


                      =====
                      "Only an admission that he does possess weapons of mass destruction
                      would do, sources said: 'The rest is just gesture politics." -- Hoon

                      "Are you still bombing your wife?" -- Winjer

                      __________________________________________________
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                    • Phil Carmody
                      ... 3330 further seconds without the prime requirement provided: 1091876084..1091876109 is len 26 ... Agreed. 5901351..5901367 is len 17 (16s) 6120922..6120939
                      Message 10 of 26 , Mar 5, 2003
                        --- "jbrennen <jack@...>" <jack@...> wrote:

                        3330 further seconds without the prime requirement provided:
                        1091876084..1091876109 is len 26

                        > --- In primenumbers@yahoogroups.com, "Jon Perry" <perry@g...> wrote:
                        > >
                        > > So I think we should adopt a policy of a least 1 prime from a range.
                        > >
                        >
                        > In that case:
                        >
                        > run length 8 -> (5255..5262)
                        > run length 9 -> (8009..8017)
                        > run length 10 -> (16268..16277)
                        > run length 11 -> (16268..16278)
                        > run length 12 -> (118151..118162)
                        > run length 13 -> (252035..252047)
                        > run length 14 -> (267485..267498)
                        > run length 15 -> (267485..267499)
                        > run length 16 -> (305923..305938)
                        >
                        > With no length 17 run less than 5*10^6.

                        Agreed.

                        5901351..5901367 is len 17 (16s)
                        6120922..6120939 is len 18 (<1s)
                        15736249..15736267 is len 19 (35s)
                        15736249..15736268 is len 20 (instant)
                        75952831..75952851 is len 21 (3m49s)
                        311606294..311606315 is len 22 (15m9s)

                        I'm just going to break the code^W^W^Wdo a few tweaks, and then I'll re-run
                        them all, and push it further. 250000/s just isn't fast enough... ;-)

                        Phil


                        =====
                        "Only an admission that he does possess weapons of mass destruction
                        would do, sources said: 'The rest is just gesture politics." -- Hoon

                        "Are you still bombing your wife?" -- Winjer

                        __________________________________________________
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                        Yahoo! Tax Center - forms, calculators, tips, more
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                      • Jon Perry
                        Are the two elements supposed to be distinct? Jon doesn t state that in his first post today. This wasn t a condition in the original discussion, indeed we
                        Message 11 of 26 , Mar 5, 2003
                          'Are the two elements supposed to be distinct? Jon doesn't state
                          that in his first post today.'

                          This wasn't a condition in the original discussion, indeed we have 4+4=8,
                          4*4+1=17, same for 2.

                          For stringency this could be added, although graphs with loops are frowned
                          at...

                          Jon Perry
                          perry@...
                          http://www.users.globalnet.co.uk/~perry/maths/
                          http://www.users.globalnet.co.uk/~perry/DIVMenu/
                          BrainBench MVP for HTML and JavaScript
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                        • Phil Carmody
                          ... You seem back-to-front, Jon. 8 is composite, 17 is prime and {1,2,3,4,5} was provided as a solution. Therefore the condition that the pair s elements are
                          Message 12 of 26 , Mar 5, 2003
                            --- Jon Perry <perry@...> wrote:
                            > 'Are the two elements supposed to be distinct? Jon doesn't state
                            > that in his first post today.'
                            >
                            > This wasn't a condition in the original discussion, indeed we have 4+4=8,
                            > 4*4+1=17, same for 2.

                            You seem back-to-front, Jon.

                            8 is composite, 17 is prime and {1,2,3,4,5} was provided as a solution.
                            Therefore the condition that the pair's elements are distinct _was_ a
                            condition in the first one?
                            If it wasn't a condition, then {1,2,3,4,5} wouldn't have been a solution.

                            > For stringency this could be added, although graphs with loops are frowned
                            > at...

                            Nope, trees and forests with loops are frowned upon (and any other DAGs, of
                            course)

                            Phil


                            =====
                            "Only an admission that he does possess weapons of mass destruction
                            would do, sources said: 'The rest is just gesture politics." -- Hoon

                            "Are you still bombing your wife?" -- Winjer

                            __________________________________________________
                            Do you Yahoo!?
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                          • Phil Carmody
                            ... 311606294..311606316 is len 23 (instant, doh!) 467282388..467282411 is len 24 (9m50s) 1142221381..1142221405 is len 25 (42m33s) It was only 4% faster
                            Message 13 of 26 , Mar 5, 2003
                              --- Phil Carmody <thefatphil@...> wrote:
                              > > run length 8 -> (5255..5262)
                              > > run length 9 -> (8009..8017)
                              > > run length 10 -> (16268..16277)
                              > > run length 11 -> (16268..16278)
                              > > run length 12 -> (118151..118162)
                              > > run length 13 -> (252035..252047)
                              > > run length 14 -> (267485..267498)
                              > > run length 15 -> (267485..267499)
                              > > run length 16 -> (305923..305938)
                              > 5901351..5901367 is len 17 (16s)
                              > 6120922..6120939 is len 18 (<1s)
                              > 15736249..15736267 is len 19 (35s)
                              > 15736249..15736268 is len 20 (instant)
                              > 75952831..75952851 is len 21 (3m49s)
                              > 311606294..311606315 is len 22 (15m9s)

                              311606294..311606316 is len 23 (instant, doh!)
                              467282388..467282411 is len 24 (9m50s)
                              1142221381..1142221405 is len 25 (42m33s)

                              It was only 4% faster looking for ones with primes in the range. So I think
                              that for me it would make sense to look for all such runs, regardless of the
                              existance of primes in the sum's range.

                              Phil


                              =====
                              "Only an admission that he does possess weapons of mass destruction
                              would do, sources said: 'The rest is just gesture politics." -- Hoon

                              "Are you still bombing your wife?" -- Winjer

                              __________________________________________________
                              Do you Yahoo!?
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                            • Jon Perry
                              These are for the isomorph a+b ab-1. (no guarenteed prime) run length 1 [1,...,1] run length 2 [2,...,3] run length 3 [5,...,7] run length 4 [56,...,59]
                              Message 14 of 26 , Mar 5, 2003
                                These are for the isomorph a+b <=> ab-1.

                                (no guarenteed prime)

                                run length 1 [1,...,1]
                                run length 2 [2,...,3]
                                run length 3 [5,...,7]
                                run length 4 [56,...,59]
                                run length 5 [121,...,125]
                                run length 6 [211,...,216]
                                run length 7 [819,...,825]
                                run length 8 [1470,...,1477]
                                run length 9 [2231,...,2239]
                                run length 10 [15886,...,15895]
                                run length 11 [44275,...,44285]
                                run length 12 [44275,...,44286]
                                run length 13 [44275,...,44287]

                                I left the code running for about an hour after I found rl13, so rl14 is
                                high.

                                Jon Perry
                                perry@...
                                http://www.users.globalnet.co.uk/~perry/maths/
                                http://www.users.globalnet.co.uk/~perry/DIVMenu/
                                BrainBench MVP for HTML and JavaScript
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                              • Phil Carmody
                                ... First ones with primes appended, and appended. ... 787374..787387 is len 14 1262441..1262455 is len 15 3623705..3623720 is len 16 7993838..7993854 is len
                                Message 15 of 26 , Mar 5, 2003
                                  --- Jon Perry <perry@...> wrote:
                                  > These are for the isomorph a+b <=> ab-1.
                                  >
                                  > (no guarenteed prime)

                                  First ones with primes appended, and appended.

                                  > run length 1 [1,...,1]
                                  > run length 2 [2,...,3]
                                  > run length 3 [5,...,7]
                                  > run length 4 [56,...,59]
                                  > run length 5 [121,...,125] 131..135
                                  > run length 6 [211,...,216]
                                  > run length 7 [819,...,825] 915..921
                                  > run length 8 [1470,...,1477] 1470..1477
                                  > run length 9 [2231,...,2239] 2231..2239
                                  > run length 10 [15886,...,15895] 42672..42681
                                  > run length 11 [44275,...,44285] 89663..89673
                                  > run length 12 [44275,...,44286] 89663..89674
                                  > run length 13 [44275,...,44287] 505989..506001

                                  787374..787387 is len 14
                                  1262441..1262455 is len 15
                                  3623705..3623720 is len 16
                                  7993838..7993854 is len 17
                                  7993838..7993855 is len 18
                                  7993838..7993856 is len 19
                                  7993838..7993857 is len 20
                                  117532072..117532092 is len 21 (6m40s)


                                  =====
                                  "Only an admission that he does possess weapons of mass destruction
                                  would do, sources said: 'The rest is just gesture politics." -- Hoon

                                  "Are you still bombing your wife?" -- Winjer

                                  __________________________________________________
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                                  Yahoo! Tax Center - forms, calculators, tips, more
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                                • thefatphil
                                  ... 535716000..535716021 is len 22 (27m35s) 535716000..535716022 is len 23 I stopped it at ~1.4G after nearly an hour looking for a 24. Phil
                                  Message 16 of 26 , Mar 5, 2003
                                    --- In primenumbers@yahoogroups.com, Phil Carmody <thefatphil@y...> wrote:
                                    > --- Jon Perry <perry@g...> wrote:
                                    > > These are for the isomorph a+b <=> ab-1.
                                    > >
                                    > > (no guarenteed prime)
                                    >
                                    > First ones with primes appended, and appended.
                                    >
                                    > > run length 1 [1,...,1]
                                    > > run length 2 [2,...,3]
                                    > > run length 3 [5,...,7]
                                    > > run length 4 [56,...,59]
                                    > > run length 5 [121,...,125] 131..135
                                    > > run length 6 [211,...,216]
                                    > > run length 7 [819,...,825] 915..921
                                    > > run length 8 [1470,...,1477] 1470..1477
                                    > > run length 9 [2231,...,2239] 2231..2239
                                    > > run length 10 [15886,...,15895] 42672..42681
                                    > > run length 11 [44275,...,44285] 89663..89673
                                    > > run length 12 [44275,...,44286] 89663..89674
                                    > > run length 13 [44275,...,44287] 505989..506001
                                    >
                                    > 787374..787387 is len 14
                                    > 1262441..1262455 is len 15
                                    > 3623705..3623720 is len 16
                                    > 7993838..7993854 is len 17
                                    > 7993838..7993855 is len 18
                                    > 7993838..7993856 is len 19
                                    > 7993838..7993857 is len 20
                                    > 117532072..117532092 is len 21 (6m40s)

                                    535716000..535716021 is len 22 (27m35s)
                                    535716000..535716022 is len 23

                                    I stopped it at ~1.4G after nearly an hour looking for a 24.

                                    Phil
                                  • Jon Perry
                                    Looking at: Check out his idea here: http://mnemo.nu/math/problems/?action=problem_view&id=107 I can t see how polytope has proved that all ab+1 are
                                    Message 17 of 26 , Mar 31, 2003
                                      Looking at:

                                      'Check out his idea here:

                                      http://mnemo.nu/math/problems/?action=problem_view&id=107'

                                      I can't see how polytope has proved that all ab+1 are composites.

                                      Indeed using this code:

                                      {
                                      forstep (n=4,20,2,v=vector(n/2);
                                      for (i=1,n/2,v[i]=n!/2+i);
                                      for (i=1,n/2,for (j=i+1,n/2,
                                      if (isprime(v[i]*v[j]+1),print(n":"i","j)))))
                                      }

                                      yields the following exceptions.

                                      16:4,7
                                      18:3,6
                                      18:5,8
                                      20:7,10
                                      20:8,9

                                      (note 16:4,7 implies that (16!/2+4) * (16!/2+7) + 1 =
                                      109440784174463838480384029 is prime)

                                      We did adopt a policy of at least one prime in the thread, as the
                                      all-composite sets seemed to be too easy; although we did not manage a proof
                                      of the existence of arbitary sets as attempted by polytope.

                                      http://groups.yahoo.com/group/primenumbers/message/11660

                                      The sets mentions are not the first composite-only runs:

                                      http://groups.yahoo.com/group/primenumbers/message/11670

                                      And

                                      http://groups.yahoo.com/group/primenumbers/message/11673

                                      sums up to current knowledge of the problem.

                                      Jon Perry
                                      perry@...
                                      http://www.users.globalnet.co.uk/~perry/maths/
                                      http://www.users.globalnet.co.uk/~perry/DIVMenu/
                                      BrainBench MVP for HTML and JavaScript
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