a(n) = n! * [x^n] 1/(1 - x)^(n*x).

Terms

a(0) =1a(1) =0a(2) =4a(3) =9a(4) =224a(5) =1650a(6) =38664a(7) =540960a(8) =13930496a(9) =291769128a(10) =8598924000a(11) =237964577400