Euler (or secant or "Zig") numbers: e.g.f. (even powers only) sec(x) = 1/cos(x).

A000364

Euler (or secant or "Zig") numbers: e.g.f. (even powers only) sec(x) = 1/cos(x).

Terms

    a(0) =1a(1) =1a(2) =5a(3) =61a(4) =1385a(5) =50521a(6) =2702765a(7) =199360981a(8) =19391512145

External references