cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A249756 Triangular array of coefficients of polynomials p(n,x) = (x + 1)*p(n-1,x) + n*x, p(0,x) = 1.

Original entry on oeis.org

1, 1, 2, 1, 5, 2, 1, 9, 7, 2, 1, 14, 16, 9, 2, 1, 20, 30, 25, 11, 2, 1, 27, 50, 55, 36, 13, 2, 1, 35, 77, 105, 91, 49, 15, 2, 1, 44, 112, 182, 196, 140, 64, 17, 2, 1, 54, 156, 294, 378, 336, 204, 81, 19, 2, 1, 65, 210, 450, 672, 714, 540, 285, 100, 21, 2, 1
Offset: 0

Views

Author

Clark Kimberling, Nov 07 2014

Keywords

Comments

(Sum of numbers in row n) = A079583(n+1) for n >= 0.

Examples

			p(0,x) = 1
p(1,x) = 1 + 2*x
p(2,x) = 1 + 5*x + 2*x^2
First 6 rows:
1
1   2
1   5    2
1   9    7    2
1   14   16   9    2
1   20   30   25   11   2
		

Crossrefs

Programs

  • Mathematica
    z = 14; p[n_, x_] := (x + 1) p[n - 1, x] + n*x; p[0, x_] = 1;
    t = Table[Factor[p[n, x]], {n, 0, z}]
    TableForm[Rest[Table[CoefficientList[t[[n]], x], {n, 0, z}]]] (* A249756 array *)
    Flatten[CoefficientList[t, x]] (* A249756 sequence *)