If you could give an in-depth explanation for the induction step of this problem, I would probably be able to do most of the other problems. I just need help getting started. Thank you very much.

Prove that 1^2 + 2^2 +....+ (2n+1)^2 = [(n+1)(2n+1)(2n+3)]/3 for all nonnegative integers.

So far, I have proven the base case of P(0) and now am stuck.