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

Terms

a(0) =1a(1) =0a(2) =-1a(3) =6a(4) =-39a(5) =295a(6) =-2589a(7) =26026a(8) =-295754a(9) =3755016a(10) =-52729546a(11) =811837268a(12) =-13601028438a(13) =246312375686