Hi Niels, > >>> mpz_add_si (p, p, diff * (odds_in_composite_sieve-1)); > > > > We don't have such a function :-) > > Ooops. > > Maybe we should have? We do have both _ui and _si versions of other > basic mpz functions, including mpz_set, mpz_mul, and mpz_cmp. mpz_addmul_si and mpz_submul_si are missing too. Paul