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

Terms

a(0) =0a(1) =1a(2) =-1a(3) =6a(4) =-22a(5) =176a(6) =-1192a(7) =12240a(8) =-122288a(9) =1561088a(10) =-20588544a(11) =318007808a(12) =-5193155328a(13) =94807748608