Expand cos x / exp x and invert nonzero coefficients.

Terms

a(0) =1a(1) =-1a(2) =0a(3) =3a(4) =-6a(5) =30a(6) =0a(7) =-630a(8) =2520a(9) =-22680a(10) =0a(11) =1247400a(12) =-7484400a(13) =97297200a(14) =0a(15) =-10216206000a(16) =81729648000a(18) =0a(22) =0