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primenumbers · Prime numbers and primality testing

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  • Members: 1090
  • Category: Number Theory
  • Founded: Dec 27, 2000
  • Language: English
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Regarding the question of Fermat factorisation, one question that has interested me is the factorisation of the ninth generalised Fermat number in base ten, or...
6 Nov 18, 2012
4:10 am

pbtoau
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This won't be log(2). Let q>2 prime (where q!=p) then x^2+(p-x)^2 != 0 mod q has got (q-2) solutions if 4|q-1 and q solutions if 4|q-3. Using this and the...
6 Nov 17, 2012
10:41 pm

djbroadhurst
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A beautiful day i made a collection of different quadratic polynoms, which produces primes according a special algorithm. i found 191 different sequences and...
27 Nov 13, 2012
3:23 pm

Mathieu Therrien
mathieu344
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"I we decompose any prime p such that p = x + y, there are (p-1)/2 forms of doing that. Of those, many can produce: x^2 + y^2 = prime. CONJECTURE. Calling...
6 Nov 11, 2012
5:51 pm

Phil Carmody
thefatphil
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Hi Guys, We can use MathJax... http://www.mathjax.org/demos/use-in-web-platforms/ MathJax in Use MathJax can be found on websites as well as apps, platforms...
2 Nov 10, 2012
3:37 pm

Phil Carmody
thefatphil
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Hi David I'm afraid I haven't the time to do this properly, (life, grr) but it appears you can write a modified Brun's sum like this C_2(X)/log x +...
1 Nov 6, 2012
11:37 pm

Guy
anastasis_1999
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Can anyone prove this : https://docs.google.com/open?id=0B5UBNPPDaeHFS05GT2JEbU96ckk <https://docs.google.com/open?id=0B5UBNPPDaeHFS05GT2JEbU96ckk&gt; best...
1 Nov 4, 2012
5:46 pm

princeps_22
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Formula for divisibility for a prime p. Maybe it can help to findfactors of a number n ?. I have found a way to find easy a formula for each prime p. Examples:...
2 Nov 2, 2012
7:34 am

Makoto Kamada
makotokamada
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I converted Bernhard's test 6 for prime numbers into a factoring algorithm. Here is one successful factoring which makes use of it. ... [168040027, 59509631,...
2 Oct 30, 2012
9:35 pm

Norman Luhn
n.luhn
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Hello all :   I need an asimtotic aproximation fot this:   Sum[d(n-p), p prime p<n]   d(i)=number of divisors of i.   (like sum [d(n) n<x] =xlogx)   Can...
2 Oct 29, 2012
10:13 pm

djbroadhurst
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A beautifull day, i have started a small collection of primes between 1000 and 10000 digit primes. The primes are all of the form p:=x^2+x+1=x(x+1)+1 I...
18 Oct 29, 2012
6:12 pm

djbroadhurst
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What are all the logic lie behind the worse running time complexity of factorization of Odd Semi-prime N = pq?...
1 Oct 29, 2012
11:26 am

kad
yourskadhir
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A famous old conjecture is that infinitely many primes of form n^2+1 exist. I have no idea how to settle that, but can one instead settle this easier problem: ...
1 Oct 26, 2012
9:10 pm

WarrenS
warren_d_smi...
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? for(p=2,10,for(q=p,10,for(r=q,10,if(p*r+q*r+p*q=p*q*r,print([p,q,r]))))) [2, 8, 2] [2, 48, 3] [2, 384, 4] [2, 3840, 5] [2, 46080, 6] [2, 645120, 7] [2,...
5 Oct 22, 2012
10:19 pm

Robin Garcia
sopadeajo2001
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Hello all:   Can anyone prove this?   ((q-p)/2)^2-(q+p)/2<0  for all p and q consecutive prime numbers p<q     Sincerely   Sebastian Martin Ruiz ...
2 Oct 22, 2012
6:22 pm

Lélio
lelio_73
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The precedent message must be read: who is failing ?...
1 Oct 22, 2012
4:18 pm

sopadeajo2001
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Hi to all, A question was asked recently. Are there infinitely many of n, n+1 both square free? A simple bit of algebra came up with the following, BUT it...
64 Oct 20, 2012
3:17 pm

Kermit Rose
kermit1941
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Hi, let X=x+2 and Y=x-2 for an integer x: Let M=[X,-1;1,2] N=[Y,-1;1,-2] Form a new matrix: A=M^2-x*M+1 Then A=2*[X,-2;2,-Y]==[2*x+4,-4;4,-2*x+4] This has the...
14 Oct 9, 2012
10:56 pm

paulunderwooduk
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... You may believe what you like. However, as I understand QED and QCD (admittedly imperfectly) there is a non-zero chance of all three quarks approaching...
3 Oct 5, 2012
4:18 pm

Paul Leyland
paul@...
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57 = 11^2 - 8^2 8 * 8 + 57 = 11 * 11 7 * 9 + 57 = 10 * 12 6 * 10 + 57 = 9 * 13 5 * 11 + 57 = 8 * 14 4 * 12 + 57 = 7 * 15 3 * 13 + 57 = 6 * 16 2 * 14 + 57 = 5 *...
1 Oct 5, 2012
12:36 am

Kermit Rose
kermit1941
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Hi! I've just started to study Theory of Numbers and I wonder if there are further evidences to the conjecture that there are infinitely manu prime-pairs...
1 Oct 5, 2012
12:06 am

Flavio Mattos
flavio_biker
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Nobody expressed any interest in this, but here is one last entry before I turned this program off.  This is a tie result.  The stem value of 126 is repeated...
1 Oct 4, 2012
5:31 pm

James Merickel
moralforce120
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Hi, I recently added 2 new sequences to OEIS. A216666 : Smallest integer b such that (b+1)^p - b^p is prime for all primes p <= prime(n). The 8 first terms are...
1 Oct 4, 2012
10:46 am

j_chrtn
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Sir, Can you please help me to find the error of this formula: See Microsoft excel file for your reference. v=Input Number ...
1 Oct 3, 2012
5:05 pm

john saccuan
saccuan_john
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For several (unconvincing) reasons I doubt it. But anyway, Kalita has a web page http://www.aec.ac.in/Uploads/File/faculty/mca/bichitra_kalita.pdf and here is...
3 Oct 3, 2012
1:51 pm

Chris Caldwell
primemogul
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Greetings , all , np ( n ) = n^n + (n+1)^(n+1) has numerous interesting aspects . Two aspects of this expression are prominent . ( 1 ) : The number of prime...
2 Oct 2, 2012
6:05 pm

Walter Nissen
nissen@...
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As you know, Dirichlet's theorem says that in any arithmetic progression a+b*n, (where a,b fixed with gcd(a,b)=1 and n is variable) there are an infinitude of...
1 Oct 2, 2012
2:43 pm

warren_d_smith31
warren_d_smi...
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 http://timesofindia.indiatimes.com/city/guwahati/Mathematician-solves-270-year-old-conjecture/articleshow/16635760.cms Steven Harvey harvey563@... ...
3 Oct 2, 2012
12:55 pm

Jens Kruse Andersen
jkand71
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If we demand that n, 2n-1, and 2n+1 all simultaneously be prime or prime-power, then initial examples found by hand are n, 2n-1, 2n+1 2, 3, 5 3, 5, 7 5, 9*, 11...
6 Oct 1, 2012
11:43 pm

WarrenS
warren_d_smi...
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How many ways can the square of an odd prime n be expressed as the sum of four non zero squares? The answer surprisingly appears to have the formula: f =...
10 Sep 28, 2012
4:37 pm

Mark
marku606
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