\(\frac{n + 1 (n - 2)}{(n + 1)!}\) \(\frac{(n + 1) + (n - 2)!(n - 2)!}{(n + 1)!}\) \(\frac{(n + 1)(n + 1 -1)(n+1-2)(n+1-3)!}{3!(n-2)!}\) \(\frac{(n + 1)(n)(n-1)(n-2)!}{3!(n-2)!}\) \(\frac{(n + 1)(n)(n-1)}{3!}\) Since n = 15 \(\frac{(15 + 1)(15)(15-1)}{3!}\) \(\frac{16 \times 15 \times 14}{3 \times 2 \times 1}\) = 560