Expansion of e.g.f.: cos(log(1+x))/cos(x).

Terms

a(0) =1a(1) =0a(2) =0a(3) =3a(4) =-11a(5) =70a(6) =-354a(7) =2415a(8) =-15763a(9) =125172a(10) =-1002604a(11) =9222455a(12) =-86960631a(13) =905535618a(14) =-9647654054a(15) =109599211995