E.g.f.: -arcsinh(x)*LambertW(-x).

Terms

a(0) =0a(1) =0a(2) =2a(3) =6a(4) =32a(5) =300a(6) =3624a(7) =52570a(8) =908928a(9) =18277560a(10) =417634080a(11) =10682763278a(12) =302517156864