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.

A154702 Triangular sequence defined by T(n, m) = Coefficients(q(x,n) + x^(n-2)*q(1/x,n))/4, where q(x, n) = d^2*P(x, n)/dx^2 and p(x, n)=(x-1)^(n+1)*Sum_{k>=0} ((-1)^(n + 1)*k^n)*x^(k-1).

Original entry on oeis.org

1, 7, 7, 36, 78, 36, 156, 624, 624, 156, 603, 4224, 7146, 4224, 603, 2157, 25281, 68322, 68322, 25281, 2157, 7318, 137622, 578130, 882340, 578130, 137622, 7318, 23938, 696970, 4433382, 9965710, 9965710, 4433382, 696970, 23938
Offset: 3

Views

Author

Roger L. Bagula, Jan 14 2009

Keywords

Comments

Row sums equal A037960(n+1) = (n + 2)!*n*(3*n + 1)/24.

Examples

			Triangle begins as:
      1;
      7,      7;
     36,     78,      36;
    156,    624,     624,     156;
    603,   4224,    7146,    4224,     603;
   2157,  25281,   68322,   68322,   25281,    2157;
   7318, 137622,  578130,  882340,  578130,  137622,   7318;
  23938, 696970, 4433382, 9965710, 9965710, 4433382, 696970, 23938;
		

Crossrefs

Cf. A037960.

Programs

  • Mathematica
    p[x_, n_] := Sum[k!*StirlingS2[n, k]*(x - 1)^(n - k), {k, 1, n}];
    (* or p[x_, n_]:= (x-1)^(n+1)*Sum[((-1)^(n+1)*k^n)*x^k, {k, 0, Infinity}]/x; *)
    q[x_, n_]:= D[p[x, n], {x, 2}];
    f[n_]:= CoefficientList[FullSimplify[ExpandAll[q[x, n]]], x];
    Table[(f[n] + Reverse[f[n]])/4, {n, 1, 10}]//Flatten (* modified by G. C. Greubel, May 08 2019 *)

Extensions

Edited by G. C. Greubel, May 08 2019