a(n) = Sum_{d|n} d*d!.

Terms

a(0) =1a(1) =5a(2) =19a(3) =101a(4) =601a(5) =4343a(6) =35281a(7) =322661a(8) =3265939a(9) =36288605a(10) =439084801a(11) =5748023639a(12) =80951270401