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

Terms

a(0) =0a(1) =1a(2) =0a(3) =-3a(4) =12a(5) =-15a(6) =-120a(7) =1197a(8) =-6048a(9) =-255a(10) =428160a(11) =-5448003a(12) =29812992a(13) =241437105a(14) =-8332047360a(15) =104019879597a(16) =-293043130368