E.g.f. log(1 + x/cos(x)).

Terms

a(0) =0a(1) =1a(2) =-1a(3) =5a(4) =-18a(5) =109a(6) =-720a(7) =5977a(8) =-56336a(9) =612729a(10) =-7453440a(11) =100954061a(12) =-1502172672a(13) =24395453861a(14) =-429076910080