Generalized Euler numbers, a(n) = n!*[x^n](sec(9*x)*(4*sin(3*x) + 2)*cos(3*x)^2).

A349268

Generalized Euler numbers, a(n) = n!*[x^n](sec(9*x)*(4*sin(3*x) + 2)*cos(3*x)^2).

Terms

    a(0) =2a(1) =12a(2) =126a(3) =2160a(4) =49410a(5) =1415232a(6) =48649086a(7) =1951153920a(8) =89434106370

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