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

Terms

a(0) =0a(1) =1a(2) =-1a(3) =2a(4) =-6a(5) =16a(6) =-72a(7) =272a(8) =-1456a(9) =7936a(10) =-47104a(11) =353792a(12) =-2390784a(13) =22368256a(14) =-180612096a(15) =1903757312a(16) =-18625189888a(17) =209865342976