E.g.f. ((e^x-1)^2*e^x) / (2*(1-(e^x-1)^3)).

Terms

a(0) =0a(1) =0a(2) =1a(3) =6a(4) =25a(5) =150a(6) =1561a(7) =16926a(8) =181945a(9) =2286150a(10) =34082521a(11) =548528046a(12) =9363855865a(13) =174531124950