Re: Mersenne: :-( TI factoring is slow

1999-06-20 Thread Anonymous
It's "testing" 2^25,000,009 - 1 right now. It can test one factor every 1.3 seconds. AUGH! At that rate it would take 95 *billion* years to trial divide by all odd numbers under 2^62. Nooo Don't forget, it's not just odd numbers, you only need to trial divide by numbers that end in 1, 3,

Re: Mersenne: :-( TI factoring is slow

1999-06-19 Thread Anonymous
However, a semi-reasonable task would be to test numbers for factors up to 2^16. Done. Pitiful, I know, but a TI could test a single number in 12 hours. An optimized algorithm will do it in about zero seconds. B) To Mr. Woltman or Mr. Kurowski - how "useful" would factoring (most likely

Mersenne: TI Factoring

1999-06-19 Thread Anonymous
[EMAIL PROTECTED] writes: So, is this: (2^p mod f) - 1 Congruent to this: (2^p -1) mod f Yes, though be careful about the case of 2^p mod f being 0. The first will give you -1 and the second is f-1. They are congruent, mod f, of course, but not identical. This is doubly