518783617205domain: NAppears in sequencesE.g.f. C(x) + S(x), where C(x)^2 - S(x)^2 = 1 and D(x)^3 - S(x)^3 = 1, and functions S(x), C(x), and D(x) are described by A280620, A280621, and A280622, respectively.at n=16A280623