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

Terms

a(0) =1a(1) =0a(2) =1a(3) =-3a(4) =20a(5) =-140a(6) =1216a(7) =-12096a(8) =137080a(9) =-1737504a(10) =24368656a(11) =-374527120a(12) =6259083896a(13) =-112992788688