E.g.f.: arcsinh(x)/(1+LambertW(-x)).

Terms

a(0) =0a(1) =1a(2) =2a(3) =11a(4) =104a(5) =1249a(6) =18264a(7) =318163a(8) =6425152a(9) =147344769a(10) =3781848480a(11) =107408279483