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2b. Re: Composite number function(2)

Kermit Rose — Fri, 20 Nov 2009 15:00:07 GMT

2b. Re: Composite number function(2) Posted by: "djbroadhurst" d.broadhurst@... djbroadhurst Date: Thu Nov 19, 2009 9:10 pm ((PST)) ... Hello David. ...

Re: Composite number function(2)

djbroadhurst — Fri, 20 Nov 2009 05:10:25 GMT

... Post hoc, ergo propter hoc? ... Your nebulous "algorithm" was surpassed 2200 years ago: http://www.gap-system.org/~history/Biographies/Eratosthenes.html

Composite number function(2)

Kermit Rose — Fri, 20 Nov 2009 04:40:35 GMT

1a. Re: Composite integer function Posted by: "Yann Guidon" whygee@... yasep16 Date: Wed Nov 18, 2009 9:02 am ((PST)) Hello Kermit, it seems that my

Re: 2^a*3^b one away from a prime

marku606 — Fri, 20 Nov 2009 04:33:22 GMT

... I think you're right Jens, infinitely many. By observation, the average number of solutions for a given prime seems to be roughly constant, around 10. For

Re: 2^a*3^b one away from a prime

Jens Kruse Andersen — Thu, 19 Nov 2009 22:39:48 GMT

... I expect infinitely many counter examples but there are none below 7500. I only computed one prime for each prime sum a+b. -- Jens Kruse Andersen

2^a*3^b one away from a prime

marku606 — Thu, 19 Nov 2009 15:59:24 GMT

Given any prime expressed as a+b, is there always some a,b such that 2^a*3^b is one away from a prime? I doubt it but have yet to find a counterexample. Below

Re: Composite integer function

Yann Guidon — Wed, 18 Nov 2009 17:02:43 GMT

Hello Kermit, it seems that my emails can't reach you due to some unexplainable blacklist on some router near you. So I answer on the list : ... ... can

Composite integer function

Kermit Rose — Wed, 18 Nov 2009 00:16:54 GMT

You might be interested in the following two variable function. Define F(m,k) recursively as follows. F(1,1) = 15 F(m+1,k) = F(m,k) + 4*(2*m + k + 2) F(m,k+1)

Re: How hard is it to find an AP-k?

mikeoakes2 — Tue, 17 Nov 2009 19:50:27 GMT

... That was as per 6 Jun. Just over 5 months on, the revised table is:- rank k d s=(k+4)*log(d) ... 1 8 1057 83.558 2 3 137514 82.817 3 12

luis galup — Sun, 15 Nov 2009 15:17:20 GMT

David, you are absolutely correct, i misstated that conjecture. the conjecture asks whether o_p(2) = p-1 for infinitely many primes. this would correspond to

Re: order of 2 in Z_p

djbroadhurst — Sun, 15 Nov 2009 11:49:29 GMT

... Counterexample: o_137(2) = (137 - 1)/2 = 68 o_p(2) is provably a divisor of p-1 for prime p. By the Artin conjecture, it is a proper divisor of p-1 for

order of 2 in Z_p

LEGalup — Sun, 15 Nov 2009 08:44:55 GMT

Greetings all, let o_p(2) = order of 2 in F_p. in other words, o_p(2) = card{ 2^0 (mod p), 2^1 (mod p), ... , 2^p (mod p) } we know that it is an open

Re: New AP16 & AP17 records

Jens Kruse Andersen — Sat, 14 Nov 2009 19:56:02 GMT

... Congratulations! http://users.cybercity.dk/~dsl522332/math/aprecords.htm is updated. That AP17 may last a while. I'm not trying to retake it. -- Jens Kruse

Finding a pair of Twin primes

mikeoakes2 — Sat, 14 Nov 2009 18:36:45 GMT

I have just submitted to Chris's database a pair of primes that, at 25055 digits, will come in at rank 16 on his Top-20 Twins page

Re: New AP16 & AP17 records

djbroadhurst — Sat, 14 Nov 2009 16:33:00 GMT

... That is, indeed, rather pleasing. Best regards, David