Expansion of e.g.f.: tanh(log(1+tanh(x))).

Terms

a(0) =0a(1) =1a(2) =-1a(3) =-2a(4) =14a(5) =-14a(6) =-286a(7) =1828a(8) =3464a(9) =-130664a(10) =619304a(11) =7421008a(12) =-128214736a(13) =153779536a(14) =18052524944a(15) =-209102239712