OK, I haven't known about that group, now I'm a member of that also. "I'm slightly confused. Isn't the first q of this form precisely q = 2p + 1? If so, it cannot be as large as your limit."
See, we are searching for primes of the form q=2kp+1, if p is prime then it isn't sure that 2p+1 is also prime, and if it is composite, then prod=1 remains, so we are still in the while loop, and we'll test q=4p+1 and so on. If I find a prime then prod*=p will be true also. If prod>bound_for_p/p then I'm exit from the while loop, I've found enough prime(s) for p (at least one prime, however for small p more than one). The following pari-gp code gives the first such q number: f(p)=q=2*p+1;while(isprime(q)==0,q+=2*p);return(q) for example f(97)=389, some "extreme" values: f(5227)=397253, so p=5227, q=397253, for this: q=1.0368*p*log(p)^2 f(170167)=24504049, so q=0.9926*p*log(p)^2 --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to mpir-devel@googlegroups.com To unsubscribe from this group, send email to mpir-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en -~----------~----~----~----~------~----~------~--~---
