A019294(461)

[Lambert Klasen]

Dear Don,

> Lambert Klasen wrote:
> > any hint for stupid me, what kind of program you use,
> > to compute this so fast ?
> 
> I find that there's usually little factoring to do. When you compute
> Y=sigma(X) as a product of numbers, keep all of those numbers; and
> at the next step, factor them instead of Y.
> Also, Y's partial products are all (b^k-1)/(b-1), and usually their
> factors can be found at http://www.cerias.purdue.edu/homes/ssw/cun
> (I didn't use that, and so my program spent many minutes refactoring
> 2^263-1.)

thx for your help!

i still get factors with
"***   Warning: MPQS: the factorization of this number will take several
hours."
not minutes ;-)
but in the meanwhile i can also happyly confirm A019294(461)=557 .


thx again and best regards
        Lambert

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