Expansion of e.g.f. exp(x)/cos(x).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =36a(6) =152a(7) =624a(8) =3472a(9) =18256a(10) =126752a(11) =814144a(12) =6781632a(13) =51475776a(14) =500231552a(15) =4381112064a(16) =48656756992a(17) =482962852096