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

Terms

a(0) =0a(1) =1a(2) =-1a(3) =2a(4) =-6a(5) =16a(6) =-72a(7) =496a(8) =-3248a(9) =24064a(10) =-208384a(11) =1908224a(12) =-19624704a(13) =227958784a(14) =-2800573440a(15) =36620830720a(16) =-519452284928