The factors of 2,811-.c239

[Jeff Gilchrist]

This was just sent to the NFSNET mailing list so I am re-posting it here for those of you that don't subscribe. This email was from Paul Leyland (aka Xilman).

Hello all.

I'm pleased that I can finally announce the factors of 2,811- aka M811
aka 2^811-1 after almost a year since NFSNET started the project. At
the time it was the largest SNFS factorization attempted.
Unfortunately, we were beaten to that record by another team.

This was a particularly arduous project. For instance, the linear
algebra had to be performed twice, for reasons that will be explained in
a later report.

Full details of the project will be reported some time in the next few
days but I wanted to let everyone here know that this appeared on my
screen a short time ago:

Factorization completed after 0.00 seconds, at Fri Jun 4 19:01:39 2004

Original number had 239 digits:
418869023306268010334103313796791513744504683537755922511342328562486335
720194909024083980191119742700408267419640678002263038674806270100102880
876354537561288709162324274723431548827216098101135346903532765963163902
62809620032306690950089

Probable prime factor 1 has 83 digits:
231198123873086951105421954667235731499996714373045780904739015214081877
60986228863

Probable prime factor 2 has 66 digits:
120561845344829717145833822890964664477289164454661659494292322521

Probable prime factor 3 has 92 digits:
150274070986336420940237249246294162405812894827912220704730573617772519
46987551028766864143

After all the earlier tribulations, it was something of a surprise to
discover the factors appeared from the first two dependencies.

Congratulations and thanks to all the NFSNET participants who helped in
finding these factors.

Paul

[BotXXX]

Good news that the factorization came through. And indeed the 3 factors are nice but sadly indeed beaten to the record of the biggest SNFS factorization todate. But ok ;) good to know it has worked. And now on to the others :D

[junky]

nice, we'll wait for future informations related to that factorisation from Paul.