81505

Appears in sequences

• Coefficient of x in the reduction by x^2 -> x+1 of the polynomial p(n,x) defined below in Comments.at n=9A192429
• Expansion of Product_{k>=1} (1 + 5*x^k).at n=22A261569
• G.f. A(x) satisfies: A(x) = x + x^2 * A(x/(1 - 4*x)) / (1 - 4*x).at n=9A351128