Expansion of cos(sin(x))/exp(x).

Terms

a(0) =1a(1) =-1a(2) =0a(3) =2a(4) =0a(5) =-16a(6) =24a(7) =104a(8) =-256a(9) =-1600a(10) =5632a(11) =29952a(12) =-156032a(13) =-644736a(14) =4761600a(15) =18383616a(16) =-178225152a(17) =-645554176a(18) =8081772544a(19) =25645936640a(20) =-422364381184