181703domain: NAppears in sequencesOdd n such that genus of modular curve X_0(N) is never equal to n.at n=9A054730Number of compositions such that the number of parts is divisible by the first part.at n=18A168655G.f. satisfies: A(x) = 1 + x*A(x)^3 + 2*x^2*A(x)^2 + x^3*A(x).at n=8A200028