-5423domain: ZAppears in sequences1-gonal pyramidal numbers.at n=32A254749E.g.f. A = A(x,y) satisfies: A^2 + B^2 + C^2 = 1 + y^2 and A^3 + B^3 + C^3 = 1 + y^3, where functions B = B(x,y) and C = C(x,y) are described by A278886 and A278887, respectively.at n=47A278885Expansion of Sum_{k>=1} x^k/(1 + k*x^k).at n=23A308367