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

Terms

a(0) =1a(1) =0a(2) =1a(3) =-3a(4) =20a(5) =-120a(6) =976a(7) =-8568a(8) =88640a(9) =-1011840a(10) =12933376a(11) =-180964608a(12) =2767631360a(13) =-45799004160a(14) =816582578176