Expansion of e.g.f. tanh(tan(x)*x) (even powers only).

A009817

Expansion of e.g.f. tanh(tan(x)*x) (even powers only).

Terms

    a(0) =0a(1) =2a(2) =8a(3) =-144a(4) =-11264a(5) =-323840a(6) =36347904a(7) =8388294656a(8) =620426657792

External references