Triangle T(n,k) = coefficient of x^n/n! in expansion of (x/cos x)^k/k!.

Terms

a(0) =1a(1) =0a(2) =1a(3) =3a(4) =0a(5) =1a(6) =0a(7) =12a(8) =0a(9) =1a(10) =25a(11) =0a(12) =30a(13) =0a(14) =1a(15) =0a(16) =240a(17) =0a(18) =60a(19) =0a(20) =1a(21) =427a(22) =0a(23) =1155a(24) =0a(25) =105a(26) =0a(27) =1a(28) =0a(29) =7616