a(n) = n! * [x^n] exp(n*x)*tanh(x).

Terms

a(0) =0a(1) =1a(2) =4a(3) =25a(4) =224a(5) =2641a(6) =38592a(7) =671665a(8) =13548544a(9) =310580161a(10) =7971353600a(11) =226406902921