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

Terms

a(0) =0a(1) =1a(2) =-2a(3) =4a(4) =-17a(5) =113a(6) =-829a(7) =6921a(8) =-68018a(9) =766909a(10) =-9668901a(11) =134950693a(12) =-2070353196a(13) =34628733267a(14) =-626969184451