121705

Appears in sequences

• Indices of the centered 12-gonal numbers which are also 12-gonal number, or numbers X such that 120*X^2-120*X+36 is a square.at n=4A133285
• Expansion of the g.f. (x^2-x+1)*(x^2-3*x+3)/(x-1)^6.at n=24A257890
• G.f.: Sum_{n>=0} (n+1)*(n+2)/2 * x^n * (1 + x^n)^n.at n=66A326003