211929

Appears in sequences

• A triangle of polynomial coefficients:{a, b, c, d} = {2, 3, 3, 2}; p(x,n)=(-1)^(n)*(1 - d - c x)^(n + 1)*Sum[(a*k + b)^n*(c*x + d)^k, {k, 0, Infinity}].at n=21A154593
• Number of zero-sum nX1 -2..2 arrays with every element equal to at least one horizontal or vertical neighbor.at n=16A201884
• Expansion of e.g.f. exp(-x) / (2 - exp(2*x)).at n=6A367977