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.

A165889 Irregular triangle T(n, k) = [x^k]( p(n, x) ), where p(n, x) = (1-x)^(2*n+4)*( Sum_{j >= 0} j^(n+1)*x^j )^2/x^2, read by rows.

Original entry on oeis.org

1, 1, 2, 1, 1, 8, 18, 8, 1, 1, 22, 143, 244, 143, 22, 1, 1, 52, 808, 3484, 5710, 3484, 808, 52, 1, 1, 114, 3853, 35032, 125746, 188908, 125746, 35032, 3853, 114, 1, 1, 240, 16782, 290672, 2000703, 6040992, 8702820, 6040992, 2000703, 290672, 16782, 240, 1
Offset: 0

Views

Author

Roger L. Bagula, Sep 29 2009

Keywords

Examples

			Irregular triangle begins as:
  1;
  1,   2,    1;
  1,   8,   18,     8,      1;
  1,  22,  143,   244,    143,     22,      1;
  1,  52,  808,  3484,   5710,   3484,    808,    52,    1;
  1, 114, 3853, 35032, 125746, 188908, 125746, 35032, 3853, 114, 1;
		

Crossrefs

Programs

  • Mathematica
    p[n_, x_]:= p[n, x]= (1/x^2)*(1-x)^(2*n+4)*Sum[k^(n+1)*x^k, {k, 0, Infinity}]^2;
    Table[CoefficientList[p[n, x], x], {n,0,12}]//Flatten (* modified by G. C. Greubel, Mar 09 2022 *)
  • Sage
    def p(n,x): return (1/x^2)*(1-x)^(2*n+4)*sum( j^(n+1)*x^j for j in (0..2*n+4) )^2
    def T(n,k): return ( p(n,x) ).series(x, 2*n+1).list()[k]
    flatten([[T(n,k) for k in (0..2*n)] for n in (0..12)])

Formula

T(n, k) = [x^k]( p(n, x) ), where p(n, x) = (1-x)^(2*n+4)*( Sum_{j >= 0} j^(n+1)*x^j )^2/x^2.
T(n, k) = [x^k]( p(n, x) ), where p(n, x) = (1-x)^(2*n+4)*( PolyLog(-n-1, x)/x)^2.
T(n, n-k) = T(n, k). - G. C. Greubel, Mar 09 2022

Extensions

Edited by G. C. Greubel, Mar 09 2022