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.

A168619 Triangle T(n,k) read by rows with the coefficient [x^k] of the polynomial (x+1)^n + (2*n-3) *( (x+1)^n -x^n -1 ) in column k, row n.

Original entry on oeis.org

1, 1, 1, 1, 4, 1, 1, 12, 12, 1, 1, 24, 36, 24, 1, 1, 40, 80, 80, 40, 1, 1, 60, 150, 200, 150, 60, 1, 1, 84, 252, 420, 420, 252, 84, 1, 1, 112, 392, 784, 980, 784, 392, 112, 1, 1, 144, 576, 1344, 2016, 2016, 1344, 576, 144, 1, 1, 180, 810, 2160, 3780, 4536, 3780, 2160, 810
Offset: 0

Views

Author

Roger L. Bagula and Gary W. Adamson, Dec 01 2009

Keywords

Comments

The term T(0,0) is defined to be 1.
Row sums are s(n) = 1, 2, 6, 26, 86, 242, 622, 1514, 3558, 8162, 18398,... (apparently with s(n) = 6*s(n-1) -13*s(n-2) +12*s(n-3)-4*s(n-4)).

Examples

			1;
1, 1;
1, 4, 1;
1, 12, 12, 1;
1, 24, 36, 24, 1;
1, 40, 80, 80, 40, 1;
1, 60, 150, 200, 150, 60, 1;
1, 84, 252, 420, 420, 252, 84, 1;
1, 112, 392, 784, 980, 784, 392, 112, 1;
1, 144, 576, 1344, 2016, 2016, 1344, 576, 144, 1;
1, 180, 810, 2160, 3780, 4536, 3780, 2160, 810, 180, 1;
		

Programs

  • Maple
    A168619 := proc(n,k)
        if n = 0 then
            1;
        else
            (1+x)^n + (2*n-3)*((1+x)^n-x^n-1) ;
            coeftayl(%,x=0,k) ;
        end if;
    end proc: # R. J. Mathar, Jul 11 2012
  • Mathematica
    p[x_, n_] := (x + 1)^n + If[n == 0, 0, (2*n - 3)]*((x + 1)^n - x^n - 1)
    a = Table[CoefficientList[p[x, n], x], {n, 0, 10}];
    Flatten[a]