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Puzzle: Counterexample for a 1+1+2 Selfridge prime test
(5)
Bernhard Helmes asked: .> Does it make any difference if the test is limited to p = 3 mod 8 in addition ? No. Here is a counterexample with composite p = 19
bhelmes_1
5
posts
10:36 AM
AP21
(1)
I have found a new record for 21 primes in arithmetic progression: AP21: 23260414913723182141+47#*n, n=0..20 (20 digits, Mar 12, 2014, Jaroslaw Wroblewski)
Jaroslaw Wroblewski
1
post
10:30 PM
First known CC18
(4)
Here is the third example: CC18 (2nd kind, 27 digit first term): 658189097608811942204322720*2^n+1, n=0..17 (Mar 9, 2014, Raanan Chermoni & Jaroslaw
Jaroslaw Wroblewski
4
posts
Mar 9
Precision
(2)
Dear sinclair75: In ill-conditioned systems and chaotic systems , precision is paramount (because a little error in the input data produces a huge error in the
mrsinclair
2
posts
Mar 8
Unsolved Problems web site update
(1)
Members of this group might be interested to know that the Unsolved Problems web site at http://unsolvedproblems.org/ http://unsolvedproblems.org/ has been
tsr21
1
post
Mar 8
AP20 - 23 digits
(2)
... Congratulations! http://users.cybercity.dk/~dsl522332/math/aprecords.htm is updated. -- Jens Kruse Andersen
Jaroslaw Wroblewski
2
posts
Mar 7
Prime 18-tuplet
(14)
Here is a new prime 18-tuplet record (and a new 18 Simultaneous Primes record): 5621078036155517013724659007 + d, d = 0, 4, 10, 12, 16, 22, 24, 30, 36, 40, 42,
Jaroslaw Wroblewski
14
posts
Feb 28
Latest Zhang improvement hearsay
(2)
Hi, ... Cool ! do you have any publicly accessible link ? yg
warren_d_smith31
2
posts
Feb 26
Re: Digest Number 3824
(2)
... You proved nothing. Rather you made a faulty heuristic and compared it with some data on small primes. Your heuristic contained one very obvious mistake:
Chris De Corte
2
posts
Feb 24
Primes in the field of |a+b*sqrt(3)*I|=1
(1)
A peaceful day to all group members and especially for Kermit and David, i would like to start a discussion about primes and some special theory concerning the
bhelmes_1
1
post
Feb 24
Probabilistic approach to prime counting
(3)
... Answer: http://mathworld.wolfram.com/MertensTheorem.html F. Mertens, "Ein Beitrag zur analytischen Zahlentheorie", J. reine angew. Math. 78 (1874) 46--62.
chrisdecorte
3
posts
Feb 23
sum of two p-smooth numbers
(11)
... The search that I recommended was http://oeis.org/search?q=1559+5711+10559+18191+31391 http://oeis.org/search?q=1559+5711+10559+18191+31391 which carefully
marku606
11
posts
Feb 16
P or NP?
(2)
... Your "next algorithm" seems to be needed when the target doubles, i.e when the number of bits increases by 1. You say this costs more than double. So the
Kermit Rose
2
posts
Feb 7
GFN3 conjecture
(5)
... It is now some time since he and his brother, Ragheb, had their profiles in the Jordan Times. Until Thamer has something of substance to communicate,
5
posts
Feb 3
Base-10 puzzle
(6)
... The first 10 members of the sequence are 31, 19, 23, 139, 6089, 40949, 13153513, 748105003, 11307204673, 202073177599 a[n] is the smallest prime that
6
posts
Feb 1
Factoring by analysis of parity
(1)
Hello everyone. I have constructed a factor algorithm that uses only the information in the base 2 representation of the number to be factored.However, it is,
Kermit Rose
1
post
Jan 26
Fermat test with gaussian base and Gaussian pseudoprimes
(3)
Paul Underwood remarked on http://arxiv.org/abs/1401.4708 [section 6] Not that there are lots of counterexamples for n = 1 mod 4. Here are are the first 3:
paulunderwooduk
3
posts
Jan 21
Bounded Gaps of Primes
(5)
... See also Harvey Dubner's paper http://oeis.org/A007534/a007534.pdf David
Bob Gilson
5
posts
Jan 14
curio on powers of e (1st appearing leading right-truncatables of ea
(1)
This is the concatenation of the first right-truncatable primes of lengths 1 to 8 (maximum) to arise as the leading digits of a positive integral power of the
James Merickel
1
post
Jan 7
Frobenius probable prime test
(2)
You can find the actual paper with a quick Google search: https://www.google.com/search?q=Grantham+Frobenius+pseudoprimes The first link for me is a link to
Kermit Rose
2
posts
Jan 5
diagram for the different fields of primes ?
(5)
... Max, Thank you for this reminder. Kermit
bhelmes_1
5
posts
Jan 2
The probability of occurrence of 3 consecutive primes
(2)
But this sequence has 3 consecutive primes {23,29,31}. What is the probability of such a occurrence? 02:03:05 03:05:07 05:07:11 07:11:13 11:13:17 13:17:19
mafshin89
2
posts
Dec 28, 2013
p-tight integers
(6)
Here is the extra step. Let a = 1 + r*p. Then S := (a^p-1)/(a-1) = sum(k=0,p-1,a^k) = sum(k=0,p-1,1+k*r*p) mod p^2 = p mod p^2, since sum(k=0,p-1,k)=p*(p-1)/2
Andrey Kulsha
6
posts
Dec 23, 2013
Endorsement
(2)
... It would appear that the author does not wish for endorsement by number theorists such as http://primes.utm.edu/bios/page.php?id=3474
mafshin89
2
posts
Dec 19, 2013
(no subject)
(1)
Here is a gp program (RL[x] is a list of x Ramanujan primes) that I am currently running (I expect it to finish by morning): n=1; j=1; c=0.0; limit=10^7;
John W. Nicholson
1
post
Dec 13, 2013
FW: TWIN PRIMES & Brun's constant? by Dimitris Valianatos GREECE.
(1)
From: dim-val@... To: dim-val@... Subject: TWIN PRIMES & Brun's constant? Date: Thu, 12 Dec 2013 04:15:13 +0200 (1/5)+Σn=1 to infinite
Dimitris Valianatos
1
post
Dec 11, 2013
Decomposition of primes
(1)
Hi, Decomposition into weight * level + jump of prime numbers : 2 trivialities: - lesser of twin prime (except 3) have a weight of 3. - by definition primes
6e788c847d3d29aefaa2be25aceec9a8
1
post
Dec 11, 2013
Three statements
(3)
... Let x = log(p_n)/n. The the inequality asserts that exp(x) > 1 + x which is true for all positive real x and hence for every prime p_n.
John W. Nicholson
3
posts
Dec 10, 2013
A "lengthy" list of prime quadruplets please?
(9)
Here it is, in a 7z file. The password is RupertWood. You must have a JRE (Java Runtime Enviromnent) installed to use it. The run.me.bat file shows how the
woodhodgson@...
9
posts
Dec 8, 2013
Using Game of Life to generate primes
(1)
Hi, I bumped into this: http://www.nathanieljohnston.com/2009/08/generating-sequences-of-primes-in-conways-game-of-life/ Christ van Willegen -- 09 F9 11 02 9D
Christ van Willegen
1
post
Dec 5, 2013
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