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

Terms

a(0) =0a(1) =1a(2) =-1a(3) =7a(4) =-20a(5) =145a(6) =-781a(7) =6711a(8) =-55040a(9) =578465a(10) =-6372241a(11) =81400295a(12) =-1118247140a(13) =17017477425a(14) =-278763221101