----- Original Message -----
From: "George Woltman" <[EMAIL PROTECTED]>
To: "Daran" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Thursday, December 05, 2002 2:35 AM
Subject: Re: Mersenne: P-1 and non k-smooth factors

> The analysis is more complex than this...

I never doubted that.  :-)

[...]

> Why not take your example:
>          "on an 8.1M exponent, B1=45000,
>          B2=731250 and varying values for D and E, I get the following
results
>          D E Stage 2 transforms
>          420 2 93946
>          420 4 98618 (the default for my memory settings)"

Done one more:

            420 6 103746

It's looking very linear.

> and write a program that emulates stage 2's selection of (x^E - d^E), does
> a prime factorization of the value, and keeps track of which factors above
> B2 get included.  It should be possible to calculate your increased chance
> of finding a factor (someone please fill in the formula here).

That's a rather more extensive programming job than the one I had in mind.
It would also be expensive at runtime, with a prime factorisation in every
cycle.

What I was thinking of, is to take the k of known Mersenne factors, or at
Brian's suggestion, random integers of an appropriate size, factor them to
obtain the second largest and largest factor, a and b, say, then emulate the
stage 2 selection of (x^E - d^E) from B1=a through to B2=b or until I find
one divisible by b, which ever comes first.

Regards

Daran


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