E.g.f. satisfies A(x) = 1 + x^3*exp(x*A(x)).

Terms

a(0) =1a(1) =0a(2) =0a(3) =6a(4) =24a(5) =60a(6) =120a(7) =5250a(8) =80976a(9) =726264a(10) =4839120a(11) =86487390a(12) =2283242280a(13) =42585905076a(14) =590667519624