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

Terms

a(0) =1a(1) =0a(2) =1a(3) =-3a(4) =4a(5) =0a(6) =16a(7) =-168a(8) =64a(9) =3840a(10) =256a(11) =-177408a(12) =1024a(13) =11182080a(14) =4096a(15) =-951886848a(16) =16384a(17) =104932638720a(18) =65536a(20) =262144a(22) =1048576a(24) =4194304a(26) =16777216