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.

Ah! ECM miss, at least by Bruce's standards :smile: or was it more efficient not to do ECM at the 60 digit level?

Regardless, great job.

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

[QUOTE=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[/QUOTE]

"difficulty is only 204"

"Only 204"??

I did this with "Only" 3 PCs.

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