44746domain: NAppears in sequencesNumber of cyclic oriented multigraphs on n labeled arcs (without loops).at n=5A020564G.f. satisfies: A(x) = 1/(1 - x*A(x)/(1 - x^2*A(x)/(1 - x^3*A(x)/(1 - x^4*A(x)/(1 - ...))))), a recursive continued fraction.at n=10A192728a(n) = a(n-1) + a(n-2) + n + 3 with n>1, a(0) = a(1) = 0.at n=19A210731