Expansion of E.g.f.: 1/(cosh(x)*cos(x)) (only powers that are multiples of 4).

A009013

Expansion of E.g.f.: 1/(cosh(x)*cos(x)) (only powers that are multiples of 4).

Terms

    a(0) =1a(1) =4a(2) =1104a(3) =2154304a(4) =15456463104

External references