E.g.f. log(1 + tanh(sinh(x))).

Terms

a(0) =0a(1) =1a(2) =-1a(3) =1a(4) =-2a(5) =1a(6) =8a(7) =1a(8) =-16a(9) =1a(10) =-2304a(11) =1a(12) =68352a(13) =1a(14) =843776a(15) =1a(16) =-221382656a(17) =1a(18) =9865887744a(19) =1a(20) =888186732544a(21) =1a(23) =1a(25) =1a(27) =1a(29) =1