353010domain: NAppears in sequences1/Product_{n>=1} (1 - a(n)*x^n) = 1 + Sum_{k>=1} F(k+1)*x^k = 1/(1-x-x^2), where F(n) = A000045(n) (Fibonacci numbers).at n=33A157162Number of regular polygons that can be drawn with vertices on a centered hexagonal grid with side length n.at n=20A339483