57921

Appears in sequences

• Enneagonal numbers whose sum of digits is also enneagonal.at n=18A117051
• p-INVERT of (1,0,0,1,0,0,1,0,0,...), where p(S) = (1 - S)(1 + S^2).at n=32A292323
• G.f.: Sum_{n>=0} (n+1) * x^n * (1 + x^n)^n.at n=80A326002