----- Original Message -----
From: "Alexander Kruppa" <[EMAIL PROTECTED]>
To: "Daran" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Monday, December 10, 2001 12:16 AM
Subject: Re: Mersenne: P-1 Stage 2

> P-1 stage 1 computes x = a^E (mod N), where E is the product of all
> primes and prime powers <= B1.

Right.  The math page says 3^(2*E*P) and neglects to mention the (mod N).
It also doesn't make it clear that E is a product of prime *powers*, and not
just a primordial.  I didn't understand how that could work, but this makes
rather more sense.

So if we were using P-1 to factorise 1000 using B1=15 we would calculate

E = 2^9 * 3^6 * 5^4 * 7^3 * 11^2 * 13^2

Or did you mean

E = 2^3 * 3^2 * 5 * 7 * 11 * 13  ?

[...]

> For each x^p_i we compute this way, we multiply this x^p_i-1 to an
> accumulator.

(Mod N) ?

This generalises surely.  You could have a third bound B3, and allow one
prime between B1 & B2, and a second prime between B1 & B3.  And then a
fourth bound B4 and so on.  (I'm not suggesting that it would be useful to
implement this.)

Thanks for a full and thought-provoking reply.

> Alex

Daran G.


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