-109824domain: ZAppears in sequencesExpansion of e.g.f. tan(tanh(x)) (odd powers only).at n=5A003721G.f. A(x) satisfies: 3^n - 1 = Sum_{k=0..n} [x^k]A(x)^n and also satisfies: (3+z)^n - (1+z)^n + z^n = Sum_{k=0..n} [x^k](A(x)+z*x)^n for all z, where [x^k]A(x)^n denotes the coefficient of x^k in A(x)^n.at n=16A100225