412826556025domain: NAppears in sequencesE.g.f. C(x) satisfies: C(x)^2 - S(x)^2 = 1 and C'(x)^2 + S'(x)^2 = 1, where S(x) is the e.g.f. of A290881.at n=7A290880E.g.f. E(x) = C(x) + S(x) such that C(x)^2 - S(x)^2 = 1 and C'(x)^2 + S'(x)^2 = 1, where C(x) is the e.g.f. of A290880 and S(x) is the e.g.f. of A290881.at n=14A290882