Quote:
Originally Posted by VBCurtis
I've wondered about this also, though my curiosity was about cofactors slightly bigger than 2*mfb but still too small to possibly split into 3 large primes.

CADO definitely deals with these properly  see this snippet from sieve/lascofactor.cpp:
Code:
nd = mpz_get_d (n);
B = (double) scs.lim;
kB = B * B;
for (klpb = lpb; klpb < s; klpb += lpb, kB *= B)
{
/* invariant: klpb = k * lpb, kB = B^(k+1) */
if (nd < kB) /* L^k < n < B^(k+1) */
return 0;
}
I couldn't find anything related to the double large prime bound, but there's a LOT of code for the siever so there's every chance I just haven't found it.