Expansion of e.g.f. log(sech(x) + arctan(x)).

Terms

a(0) =0a(1) =1a(2) =-2a(3) =3a(4) =-8a(5) =53a(6) =-320a(7) =1799a(8) =-14464a(9) =154985a(10) =-1601152a(11) =16589771a(12) =-211517440a(13) =3172731677a(14) =-47440986112a(15) =721614303695