n^n + n! - 2*(n+1)^(n-1).

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =30a(5) =653a(6) =13762a(7) =304295a(8) =7251598a(9) =187783369a(10) =5287733418a(11) =161516858963