In pysymbolicext.c, function factor_using_pollard_rho has variables k, l, c, and i are of type int. This limits the number of test cycles since int variables will wrap around to zero when doubling from 2^30 to 2^31 to 2^32. Using mpz_t variables corrects the problem.

Thanks for the report and patch. I'm testing the patch and should get it committed over the weekend.

casevh

Patch submitted as r19.