Expansion of e.g.f.: exp(x)/cosh(tanh(x)).

Terms

a(0) =1a(1) =1a(2) =0a(3) =-2a(4) =8a(5) =56a(6) =-216a(7) =-2344a(8) =12032a(9) =168640a(10) =-1075328a(11) =-18467712a(12) =140944000a(13) =2863703168a(14) =-25464568832a(15) =-597301399296