On Tue, Oct 12, 1999 at 10:53:18PM -0400, Darxus wrote: > > I'm hoping what I have to say in this email might be important. > > On Tue, 12 Oct 1999, George Woltman wrote: > > > At 04:12 PM 10/12/99 -0400, you wrote: > > >> >And how is the probability of finding a prime calculated ? > > >> > > >> It is roughly how-far-factored-in-bits * 2 / exponent > > > > > >Okay.. what's "how-far-factored-in-bits" mean ? > > > > I think trial factoring is done to 2^68 for an exponent around 33 million. > > Thus your chance is 2 * 68 / 33000000. > > Okay, so as far as we know, each number is equally likely to be prime, and > this probability is just based on how much has already been tested ? No, they're saying the probability is based on how deeply they've tried to factor the number before trying the LL test. The more numbers N you rule out as potential factors of M, the more likely M is to be prime. Also, although there are an infinite number of primes, their density thins out considerably as they get large because there are so many more potential factors below them. This applies to primes in general; I don't know if it applies to Mersenne primes. _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
