2^877-1: let the sieving commence! - Page 3

bsquared · 2009-07-21, 14:29

Quote:

Originally Posted by Primeinator

Oh, I was not aware that 877 was composite. I just assumed it was prime and that 2^877 -1 was composite (obviously) because you were attempting to completely factor it.

It's prime. What he's saying is that only mersenne's with exponents of composite multiples of 877 will benefit from this work. Since the projects you mention only work on prime exponents, they won't benefit.

Primeinator · 2009-07-21, 15:10

Quote:

Originally Posted by bsquared

It's prime. What he's saying is that only mersenne's with exponents of composite multiples of 877 will benefit from this work. Since the projects you mention only work on prime exponents, they won't benefit.

Oh, okay. That makes sense.

10metreh · 2009-07-21, 15:18

BTW, the reason no-one is looking at composite exponents in that range (unless they are of really special form) is because they can't be primes, and the only reason LMH, 100mdpp and OBD exist is to rule out Mersenne prime candidates. Factoring the composites is too hard at that size.

J.F. · 2009-07-21, 15:49

I have a very good use for factors of Mersenne's: they can be used to generate base-2 pseudoprimes.

Primeinator · 2009-07-21, 16:49

Quote:

Originally Posted by J.F.

I have a very good use for factors of Mersenne's: they can be used to generate base-2 pseudoprimes.

Which serves what purpose?

axn · 2009-07-21, 16:54

Quote:

Originally Posted by Primeinator

Which serves what purpose?

Ah! One of those "infinite regress" guys, are you?

Primeinator · 2009-07-21, 17:03

Quote:

Originally Posted by axn

Ah! One of those "infinite regress" guys, are you?

I am not familiar with that term. I am merely asking if constructing a list of Mersenne number pseudoprimes is of mathematical value or is strictly done for interest- I can relate to both and I ask because this is outside of my knowledge in math, which is more of a hobby for me. My major is actually in biology.

Edit:

Quote:

An infinite regress in a series of propositions arises if the truth of proposition P1 requires the support of proposition P2, and for any proposition in the series Pn, the truth of Pn requires the support of the truth of Pn+1. There would never be adequate support for P1, because the infinite sequence needed to provide such support could not be completed.

No, I would not define myself as this. However, I do like having my ducks in a row. I suppose you could say I am somewhat OCD

bsquared · 2009-07-22, 14:11

Quote:

Originally Posted by bsquared

Reserving 102-120

Done. 24493932 relations in 25.1Msec on k8/1400.

Reserving 126-144.

Andi47 · 2009-07-22, 15:16

My range has finished ~1 week ago and I have just realized that the relations are still sitting on my harddisc and waiting for me to upload them. I will start uploading in approx. 2 hours from now.

P.S.: My (relatively small) ressources are currently tied up with a GNFS-153 (2,1766M), so I will not reserve more ranges here.

fivemack · 2009-08-16, 09:57

Just reporting that 82-98 successfully completed while I was in Canada.

I've picked up 80-82, 102-120 and 120-122.

bsquared · 2009-08-17, 14:17

Welcome back!

126-144 is on its way up. I forgot to count relations before I tarred them, but it took about 25.4 Msec (k8/1400).

I'll take 148-164.

[edit]
the upload failed some small percentage of the way through. I'm breaking the gzip'ed file up into several parts and will try again piece by piece.

2009-07-21, 15:18	#25
10metreh Nov 2008 2×3³×43 Posts	BTW, the reason no-one is looking at composite exponents in that range (unless they are of really special form) is because they can't be primes, and the only reason LMH, 100mdpp and OBD exist is to rule out Mersenne prime candidates. Factoring the composites is too hard at that size. Last fiddled with by 10metreh on 2009-07-21 at 15:18

2009-08-17, 14:17	#33
bsquared "Ben" Feb 2007 3×1,171 Posts	Welcome back! 126-144 is on its way up. I forgot to count relations before I tarred them, but it took about 25.4 Msec (k8/1400). I'll take 148-164. [edit] the upload failed some small percentage of the way through. I'm breaking the gzip'ed file up into several parts and will try again piece by piece. Last fiddled with by bsquared on 2009-08-17 at 14:41

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2009-07-21, 15:49	#26
J.F. Jun 2008 2³×3² Posts	I have a very good use for factors of Mersenne's: they can be used to generate base-2 pseudoprimes.

2009-07-22, 15:16	#31
Andi47 Oct 2004 Austria 2·17·73 Posts	My range has finished ~1 week ago and I have just realized that the relations are still sitting on my harddisc and waiting for me to upload them. I will start uploading in approx. 2 hours from now. P.S.: My (relatively small) ressources are currently tied up with a GNFS-153 (2,1766M), so I will not reserve more ranges here.

2009-08-16, 09:57	#32
fivemack (loop (#_fork)) Feb 2006 Cambridge, England 7²×131 Posts	Just reporting that 82-98 successfully completed while I was in Canada. I've picked up 80-82, 102-120 and 120-122.