Expansion of e.g.f. exp(tan(x)^2) (even powers only).

A009256

Expansion of e.g.f. exp(tan(x)^2) (even powers only).

Terms

    a(0) =1a(1) =2a(2) =28a(3) =872a(4) =47248a(5) =3907232a(6) =454886848a(7) =70597546112

External references