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.

A167884 Triangle read by rows: T(n,k) given by T(n, 1) = T(n,n) = 1, otherwise T(n, k) = (m*n-m*k+1)*T(n-1,k-1) + (m*k-m+1)*T(n-1,k), where m = 8.

Original entry on oeis.org

1, 1, 1, 1, 18, 1, 1, 179, 179, 1, 1, 1636, 6086, 1636, 1, 1, 14757, 144362, 144362, 14757, 1, 1, 132854, 2941135, 7218100, 2941135, 132854, 1, 1, 1195735, 55446309, 277509955, 277509955, 55446309, 1195735, 1, 1, 10761672, 1001178268, 9211047544, 18315657030, 9211047544, 1001178268, 10761672, 1
Offset: 1

Views

Author

Roger L. Bagula, Nov 14 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,       1;
  1,      18,        1;
  1,     179,      179,         1;
  1,    1636,     6086,      1636,         1;
  1,   14757,   144362,    144362,     14757,        1;
  1,  132854,  2941135,   7218100,   2941135,   132854,       1;
  1, 1195735, 55446309, 277509955, 277509955, 55446309, 1195735, 1;
		

Crossrefs

For m = ...,-2,-1,0,1,2,3,4,5,6,7,8, ... we get ..., A225372, A144431, A007318, A008292, A060187, A142458, A142459, A142460, A142461, A142462, A167884, ...
Cf. A084948 (row sums).

Programs

  • Mathematica
    T[n_, k_, m_]:= T[n, k, m]= If[k==1 || k==n, 1, (m*n-m*k+1)*T[n-1, k-1, m] + (m*k-m+1)*T[n-1, k, m]];
    A167884[n_, k_]:= T[n,k,8];
    Table[A167884[n, k], {n,12}, {k,n}]//Flatten (* modified by G. C. Greubel, Mar 18 2022 *)
  • Sage
    @CachedFunction
    def T(n,k,m):
        if (k==1 or k==n): return 1
        else: return (m*(n-k)+1)*T(n-1,k-1,m) + (m*k-m+1)*T(n-1,k,m)
    def A167884(n,k): return T(n,k,8)
    flatten([[ A167884(n,k) for k in (1..n)] for n in (1..15)]) # G. C. Greubel, Mar 18 2022

Formula

T(n, k) = (m*n-m*k+1)*T(n-1,k-1) + (m*k-m+1)*T(n-1,k), with T(n, 1) = T(n, n) = 1, and m = 8.
Sum_{k=1..n} T(n, k) = A084948(n-1).

Extensions

Edited by N. J. A. Sloane, May 08 2013