Arguably the Right Answer wouldn't filter on a generator of all permutations but would generate the permutations in a way that didn't include invalid ones to be

Arguably the Right Answer wouldn't filter on a generator of all permutations but would generate the permutations in a way that didn't include invalid ones to begin with. Something like: def extend(perm): for k in range(1,11): if k not in perm and isprime(k + perm[-1]): yield [*perm, k] perms = [[]] for _ in range(10): perms = [extend(perm) for perm in perms] (This is just a draft, but you get the gist)