129133602

Appears in sequences

• Expansion of x^2*(1-x)/((1-3*x)*(1-3*x^2)).at n=18A122006
• Expansion of 2*x^2*(1-2*x) / ((3*x-1)*(3*x^2-1)).at n=18A122007
• a(n) = 3^(n-1)*(3^n - 1), n >= 0.at n=9A219205