[seqfan] Re: Artur (by way of O. Gérard) Help Needed for factorization

[Joshua Zucker]

On Thu, Nov 20, 2008 at 8:25 AM, Olivier Gerard
<olivier.gerard at gmail.com> wrote:
> Mathematica tried factoring on my machine
>
> 1330560206356479874437581808691225710711634173623638361001698161624807\
> 9279126427105233053103284238007262282978961283301626482919922623957738\
> 2611453884961785422078720891479787457044659989325136247370735966256412\
> 9863013583118913903182578923381081567912635533663584632871383920445968\
> 5713267042987
>
> for three days.
>
> I have written a procedure to extract relatively quickly "small"
> divisors and now I have to factor
>
> 1966382802018295849983426140507775310581529713937897353137000391612422\
> 8278817175390596880190641015445045632436171849324612595906231468275752\
> 7061637282120947925875224843503921645170678491988278295011723585321614\
> 64349494218512454182166238160960541165661049938151951871347
>
> and the next prime divisor should be of the form 486 k + 1 and k>1000001

Unless I made a typo cutting and pasting this big number, I
immediately find 3110690934667 as a divisor, but the remaining big
composite is still somewhat harder ...  OK, it has
216892513252489863991753 as a factor, and 1102099161075964924744009
also, and there's still a remaining BIG composite ...



> And a general question to all seqfans:
> ==============================
>
> someone sent on the list about one year ago a link to a server where I
> could do advanced prime
> factorization on a fast computer system, but I cannot find the link again.
>
> Could someone send me the link again ?

Maybe http://www.alpertron.com.ar/ECM.HTM ?

--Joshua Zucker