Expansion of exp(x)/cosh(tan(x)).

Terms

a(0) =1a(1) =1a(2) =0a(3) =-2a(4) =-8a(5) =-24a(6) =-56a(7) =-104a(8) =512a(9) =5824a(10) =54912a(11) =385408a(12) =2590336a(13) =15920256a(14) =69311488a(15) =160063744a(16) =-3936710656a(17) =-67251703808a(18) =-914002857984