C166 from 10^455-1?

[schickel]

Originally Posted by Stargate38

Do you have an ETA? This number is #5 among the 10 smallest composites in the Repunit Factorizations:

http://homepage2.nifty.com/m_kamada/math/11111.htm

I love to see the new factors. It makes me happy.

Originally Posted by schickel

I'd be willing to pay $5 if you factored it and then posted the factors a digit at a time over the course of a week...

This offer is still open....

[chris2be8]

Sun Jan 29 00:17:21 2012 prp75 factor: 139397282236319122569927698220829009751930337603755594300386510230285560351
Sun Jan 29 00:17:21 2012 prp92 factor: 32647385051525041661479792654516355809315046496410663779745524799749707387460867800164362111

Chris K

PS. M. Kamada hasn't heard of anyone else working on R870 so I'll start on it. I think ECM to 50 digits is enough, T55 would take about two weeks for a 10% chance of a factor while GNFS will take 4-5 weeks for a 100% chance.

[wreck]

I think you should chat with Yousuke Koide first before you start the fatoring of M870, he has done 18400@12e7 of M870, and this number is marked with (reserved GNFS) ,
the url is
http://www.h4.dion.ne.jp/~rep/table3.htm
you can have his email from http://www.h4.dion.ne.jp/~rep/

Bo Chen

[debrouxl]

FWIW, my computer ran 673 curves at B1=11e6 before I saw your message and ended the tasks.
No factor found, unsurprisingly, if the number has already received more than t55 ECM work

[Batalov]

Originally Posted by Batalov

Also, if you do want to take on a c166 c162, then why not on a Wanted Cunningham c163? It was deliberately left for enthusiasts.

This is a much safer offer. This number (3^710+1 cofactor) is still unreserved - write to Sam.

[chris2be8]

OK, I'll leave it to Yousuke Koide. He reserved it first.

Chris