a(n) = Sum_{k=1..n} k*k!*C(n,k).

Terms

a(0) =0a(1) =1a(2) =6a(3) =33a(4) =196a(5) =1305a(6) =9786a(7) =82201a(8) =767208a(9) =7891281a(10) =88776910a(11) =1085051121a(12) =14322674796a(13) =203121569833