3001316domain: NAppears in sequencesExpansion of (1+x^3*C^2)*C^2, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.at n=13A071731Expansion of (1+x^4*C^4)*C^2, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.at n=13A071755