17709, "lydia-duncan", "BigInteger module missing routines?", "2021-05-12T21:58:47Z"
bigint.fac() but we don't provide the double factorial or multi-factorial versions. GMP has them in its documentation and they are in the GMP module but we don't have a bigint version. Should we?
mpz_primorial_ui() is also not covered. Should it be? (It is in the GMP module)