sieve_prime_cluster(3,6,8) returns incorrect values

[trizen]

There seems to be a minor inconsistency between Math::Prime::Util::sieve_prime_cluster() and Math::Prime::Util::GMP::sieve_prime_cluster() on certain inputs.

Example:

use 5.010;
use Math::Prime::Util qw();
use Math::Prime::Util::GMP qw();

say join(' ', Math::Prime::Util::sieve_prime_cluster(3,6,8));
say join(' ', Math::Prime::Util::GMP::sieve_prime_cluster(3,6,8));

Output:

3 5
5