122311

Appears in sequences

• Expansion of (1-x)^(-1)/(1-2*x+x^2+2*x^3).at n=21A077857
• Expansion of e.g.f. exp(x*(1 + 3*x + 6*x^2 + 3*x^3 + x^4)/(1 - x^2)^3).at n=6A308418