Expansion of cosh(tanh(log(1+x))).

Terms

a(0) =1a(1) =0a(2) =1a(3) =-3a(4) =4a(5) =20a(6) =-224a(7) =1344a(8) =-5144a(9) =-4320a(10) =356896a(11) =-4755520a(12) =42368536a(13) =-207434448a(14) =-1593929336a(15) =61487349000a(16) =-997231605824