2,791+

R.D. Silverman · 2005-08-18, 23:52

Hi,

Here is 2,791+ C192 = p58.p135

p58 = 1621080768750408973059704415815994507256956989913429764153
p135 = 332481381958220346599082710923771255660980013736141639215502033762751013582088798815990776059210975124107935798363184741320908696967121

I have finished sieving 2,969+ and am starting the filtering now.
I just started sieving 2,993+ and will then do 2,1322M.

garo · 2005-08-19, 00:02

Ah! ECM miss, at least by Bruce's standards

or was it more efficient not to do ECM at the 60 digit level?

Regardless, great job.

akruppa · 2005-08-19, 09:28

Thanks to 791 = 7 * 113, the difficulty is only 204 with a well-suited sextic. By the 2/9-th rule, ECM to 45 digits would have sufficed to justify switching to SNFS. This was not an ECM miss, SNFS was definitely right for this one.

Alex

R.D. Silverman · 2005-08-19, 10:24

Quote:

Originally Posted by akruppa

Thanks to 791 = 7 * 113, the difficulty is only 204 with a well-suited sextic. By the 2/9-th rule, ECM to 45 digits would have sufficed to justify switching to SNFS. This was not an ECM miss, SNFS was definitely right for this one.

Alex

"difficulty is only 204"

"Only 204"??

I did this with "Only" 3 PCs.

akruppa · 2005-08-19, 10:51

As far as the remaining composites in the Cunningham tables go, difficulty 200 is pretty easy - I didn't see too many with lower difficulty, and those that are there mostly require a degree 4 polynomial, so they will be harder to sieve than the difficulty tells. Imho difficulty 200 does not qualify as a real challenge anymore these days - it's something we do all the time, have been doing for a while and is a long shot from requiring an extraordinary effort such as testing ECM to 60 digits first - hence the "only". Note that I'm not say that there's not a lot of work involved in such a factorisation. I've done enough of them to know better than that.

Alex

2005-08-18, 23:52	#1
R.D. Silverman Nov 2003 2²×5×373 Posts	2,791+ Hi, Here is 2,791+ C192 = p58.p135 p58 = 1621080768750408973059704415815994507256956989913429764153 p135 = 332481381958220346599082710923771255660980013736141639215502033762751013582088798815990776059210975124107935798363184741320908696967121 I have finished sieving 2,969+ and am starting the filtering now. I just started sieving 2,993+ and will then do 2,1322M.

2005-08-19, 00:02	#2
garo Aug 2002 Termonfeckin, IE 2²·691 Posts	Ah! ECM miss, at least by Bruce's standards or was it more efficient not to do ECM at the 60 digit level? Regardless, great job.

2005-08-19, 09:28	#3
akruppa "Nancy" Aug 2002 Alexandria 2,467 Posts	Thanks to 791 = 7 * 113, the difficulty is only 204 with a well-suited sextic. By the 2/9-th rule, ECM to 45 digits would have sufficed to justify switching to SNFS. This was not an ECM miss, SNFS was definitely right for this one. Alex

2005-08-19, 10:51	#5
akruppa "Nancy" Aug 2002 Alexandria 4643₈ Posts	As far as the remaining composites in the Cunningham tables go, difficulty 200 is pretty easy - I didn't see too many with lower difficulty, and those that are there mostly require a degree 4 polynomial, so they will be harder to sieve than the difficulty tells. Imho difficulty 200 does not qualify as a real challenge anymore these days - it's something we do all the time, have been doing for a while and is a long shot from requiring an extraordinary effort such as testing ECM to 60 digits first - hence the "only". Note that I'm not say that there's not a lot of work involved in such a factorisation. I've done enough of them to know better than that. Alex