| j | fac(2 * i) / (fac(2 * i - i) * fac(i)), 2 * i < j, prime(j), 0 < i, 0 ≤ i ⊦ |
⊦ i ≤ j ∧ 0 ≤ i → fac(j - i) * fac(i) | fac(j)
i ≤ 2 * i ∧ 0 ≤ i → fac(2 * i - i) * fac(i) | fac(2 * i), j | fac(2 * i) / (fac(2 * i - i) * fac(i)), 2 * i < j, prime(j), 0 < i, 0 ≤ i ⊦
Used terms: i, 2 * i