a(n) = n! * Sum_{k=0..n} k^4 / k!.

Terms

a(0) =0a(1) =1a(2) =18a(3) =135a(4) =796a(5) =4605a(6) =28926a(7) =204883a(8) =1643160a(9) =14795001a(10) =147960010a(11) =1627574751a(12) =19530917748a(13) =253901959285