Prove by induction that n(n + 1)(n + 2) is divisible by 6
When n = 1, n(n + 1)(n + 2) = 6, which obviously works
Assume true for n = k, i.e. k(k + 1)(k + 2) = 6M
Consider n = k + 1
(k + 1)(k + 2)(k + 3) = 6M/k (k + 3) <--- how do i prove this is divisible by 6?