Expansion of log(1+tan(x))/cosh(x).

Terms

a(0) =0a(1) =1a(2) =-1a(3) =1a(4) =-8a(5) =65a(6) =-361a(7) =2497a(8) =-23848a(9) =256385a(10) =-2904601a(11) =36778113a(12) =-520366208a(13) =8014148545a(14) =-132884846641