Loading ...
Sorry, an error occurred while loading the content.
 

AP20 diff 53#

Expand Messages
  • Jaroslaw Wroblewski
    I just got AP20 with difference 53#: 178284683588844176017 + 53#*n, n=0..19 It took me 10 days with 30 64-bit computers (although some of them were not working
    Message 1 of 4 , Feb 19, 2007
      I just got AP20 with difference 53#:

      178284683588844176017 + 53#*n, n=0..19

      It took me 10 days with 30 64-bit computers (although some of them were
      not working all the time). It is really hard to get a progression that
      long with terms having more than 64 bits. Frankly, I was loosing hope I
      could get it in a reasonable time.

      Jarek
    • Jens Kruse Andersen
      ... Congratulations on yet another AP record! http://hjem.get2net.dk/jka/math/aprecords.htm#history20 Up towards 300 64-bit cpu days to set your 6th successive
      Message 2 of 4 , Feb 20, 2007
        Jaroslaw Wroblewski wrote:
        > 178284683588844176017 + 53#*n, n=0..19
        >
        > It took me 10 days with 30 64-bit computers
        > (although some of them were not working all the time).
        > It is really hard to get a progression that long with
        > terms having more than 64 bits. Frankly, I was loosing
        > hope I could get it in a reasonable time.

        Congratulations on yet another AP record!
        http://hjem.get2net.dk/jka/math/aprecords.htm#history20
        Up towards 300 64-bit cpu days to set your 6th successive AP20 record in
        two months?

        Those of us with one old computer may have another perspective
        of "reasonable time".

        --
        Jens Kruse Andersen (envious)
      • Jaroslaw Wroblewski
        Thanks. With one new, but 32-bit computer, this search would take a few years. And moreover I think I was quite lucky too, although I cannot give an estimate
        Message 3 of 4 , Feb 20, 2007
          Thanks.

          With one new, but 32-bit computer, this search would take a few years.
          And moreover I think I was quite lucky too, although I cannot give an
          estimate how long on average I should wait for an AP20. Anyway, this
          AP20 was the first sequence longer than 18 terms in 10 days, but I think
          on average I should have expected at least a few AP19's by now. So I was
          very unlucky to wait so long for the first AP19+, but was rewarded to
          get AP20 as the first AP19+.

          I was really afraid I may get no AP20 in a month or two (now I was using
          the computers day and night, but when students start classes next week,
          comps will not be available during the day).

          My previous search on difference 53# gave me AP19 very quickly, so
          starting this AP20 search I was very optimistic. If I knew how hard it
          was going to get another progression longer than 18 terms, I would
          have thought twice before going into this search. Fortunately I didn't
          realize what I was going into and once the search was launched I didn't
          want to abandon it. And I was lucky again to get AP20 sooner than it
          should appear on average.

          Given that the computers were not needed for any other project, 10 day
          wait for 21 digit AP20 was still reasonable from my perspective.

          Jarek

          > Jaroslaw Wroblewski wrote:
          > > 178284683588844176017 + 53#*n, n=0..19
          > >
          > > It took me 10 days with 30 64-bit computers
          > > (although some of them were not working all the time).
          > > It is really hard to get a progression that long with
          > > terms having more than 64 bits. Frankly, I was loosing
          > > hope I could get it in a reasonable time.
          >
          > Congratulations on yet another AP record!
          > http://hjem.get2net.dk/jka/math/aprecords.htm#history20
          > Up towards 300 64-bit cpu days to set your 6th successive AP20 record in
          > two months?
          >
          > Those of us with one old computer may have another perspective
          > of "reasonable time".
          >
          > --
          > Jens Kruse Andersen (envious)
          >
        • David Broadhurst
          ... Good fortune often comes via that route; sometimes ignorance of diffculty is a blessing. David, adding to previous congratulations
          Message 4 of 4 , Feb 20, 2007
            --- In primeform@yahoogroups.com, Jaroslaw Wroblewski
            <Jaroslaw.Wroblewski@...> wrote:

            > Fortunately I didn't realize what I was going into and
            > once the search was launched I didn't want to abandon it.

            Good fortune often comes via that route;
            sometimes ignorance of diffculty is a blessing.

            David, adding to previous congratulations
          Your message has been successfully submitted and would be delivered to recipients shortly.