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

Terms

a(0) =0a(1) =1a(2) =-1a(3) =-3a(4) =8a(5) =25a(6) =-121a(7) =-427a(8) =3128a(9) =12465a(10) =-124921a(11) =-555731a(12) =7158128a(13) =35135945a(14) =-557749921a(15) =-2990414715a(16) =56767019408a(17) =329655706465