631 % i = 0, 1 < i, 0 < i, i < 20, i * i ≤ 631 ⊦
Used simplifier rules: ⊦ i ≤ j ↔ ¬ j < i; (ss)%j0 ≠ 0, j < j0 ⊦ i < (* j) → i < (* j0); (s)