Hello codeforces community!!

On this occasion I bring up a combinatorics problem.

This is the problem:

How many permutations of length N exist such that the following holds: for each i (1 <= i < N) p[i+1] — p[i] != 1

Constants: 1 <= N <= 500

Hello Codeforces!!

I saw this problem days ago and I have tried to solve it since then but I have not been successful. Help me please

This is the problem