Big factors
Found my biggest factor so far for a Wagstaff number:
2^9235649+1 has a factor: 153616228560877782360733142221974579132477827835600631264993134521609 [226.5 bits] 
worktodo.txt:
Pminus1=1,2,8232929,1,10000,0,"3" => [CODE]P1 found a factor in stage #1, B1=10000. 2^8232929+1 has a factor: 997183410304432117267065463213026379715216410911450070172292068758243 [/CODE] [That's 229.2 bits] [SPOILER] (Of course, I cheated in Pari first, by finding a few 2^p+1 that have at least five small factors. This one has two more slightly larger. Seven altogether.) [/SPOILER] 
Congratulations, Jeff!

Have you submitted them to Zimmermann's website?
[url]http://www.loria.fr/~zimmerma/records/Pminus1.html[/url] 
Composite factors are not eligible:
153616228560877782360733142221974579132477827835600631264993134521609 = 7160401272398244691 * 219902328863708115073 * 97559577016295905770143558963 The smallest of them should have been found by TF, easily: 62 bits. (Wagstaff numbers have factors of form 2kp+1, just like Mersenne's.) Let's find some even larger factors... [CODE]P1 found a factor in stage #1, B1=100000. 2^8232929+1 has a factor: 8203927240046868961280630569987984778892578839825012457683394506843242760078451651993971 [/CODE] [292 bits] 
Vincent TF'd Jeff's Wagstaff candidate to 61 bits :smile:

Damn. But it's pretty cool to find a factor that divides into three other ones. :smile:

[QUOTE=paulunderwood;335928]Vincent TF'd Jeff's Wagstaff candidate to 61 bits :smile:[/QUOTE]
Isn't it fairly obvious to use a slightly revised mfaktc for that? This is how far you guys TF? 61 bits? This is very low. 
[QUOTE=Batalov;335988]Isn't it fairly obvious to use a slightly revised mfaktc for that?
This is how far you guys TF? 61 bits? This is very low.[/QUOTE] Don't forget that TF to 61 bits for a number with p=9M is much harder than TF to 61 with p=64M. I think it's more like TFing p=64M to 64 bits...that still seems low, but for p=9M, maybe that's sufficient. Maybe they don't have an mfaktc equivalent. ("wfaktc"?) 
Oliver has modified his GPU code and Jeff is testing it now. Vincent should be firing up a couple of Teslas soon. :smile:

As Paul said, we are factoring to high bits now with the modified version of mfaktc. That P1 factor was from the last batch of p1 before I started using it.
GPU TF FTW! 
All times are UTC. The time now is 19:14. 
Powered by vBulletin® Version 3.8.11
Copyright ©2000  2020, Jelsoft Enterprises Ltd.