E.g.f. cos(cos(x)-1) (even part).

Terms

a(0) =1a(1) =0a(2) =-3a(3) =15a(4) =42a(5) =-2895a(6) =54417a(7) =-251160a(8) =-32268603a(9) =1859064495a(10) =-56137896318a(11) =-300966155655