E.g.f.: log((1-x)/(1-2*x))*x/(1-x).

Terms

a(0) =0a(1) =0a(2) =2a(3) =15a(4) =116a(5) =1030a(6) =10644a(7) =127428a(8) =1750944a(9) =27325296a(10) =479288160a(11) =9355658400a(12) =201405744000