E.g.f.: artanh(x*exp(x)).

Terms

a(0) =1a(1) =2a(2) =5a(3) =28a(4) =209a(5) =1806a(6) =18997a(7) =235544a(8) =3322881a(9) =52688890a(10) =929147141a(11) =18023207412a(12) =381330466321