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

Terms

a(0) =0a(1) =1a(2) =-1a(3) =3a(4) =-10a(5) =65a(6) =-376a(7) =2723a(8) =-22800a(9) =226785a(10) =-2467456a(11) =29857443a(12) =-397200640a(13) =5785047905a(14) =-91090625536