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.

A135087 Triangle T(n, k) = 2*A134058(n, k) - 1, read by rows.

Original entry on oeis.org

1, 3, 3, 3, 7, 3, 3, 11, 11, 3, 3, 15, 23, 15, 3, 3, 19, 39, 39, 19, 3, 3, 23, 59, 79, 59, 23, 3, 3, 27, 83, 139, 139, 83, 27, 3, 3, 31, 111, 223, 279, 223, 111, 31, 3, 3, 35, 143, 335, 503, 503, 335, 143, 35, 3
Offset: 0

Views

Author

Gary W. Adamson, Nov 18 2007

Keywords

Examples

			First few rows of the triangle are:
  1;
  3,  3;
  3,  7,  3;
  3, 11, 11,  3;
  3, 15, 23, 15,  3;
  3, 19, 39, 39, 19,  3;
  3, 23, 59, 79, 59, 23, 3;
  ...
		

Crossrefs

Programs

  • Magma
    [1] cat [4*Binomial(n,k) -1: k in [0..n], n in [1..12]]; // G. C. Greubel, May 03 2021
    
  • Mathematica
    Table[4*Binomial[n, k] -2*Boole[n==0] -1, {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, May 03 2021 *)
  • Sage
    def A135087(n,k): return 4*binomial(n,k) -2*bool(n==0) -1
    flatten([[A135087(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, May 03 2021

Formula

T(n, k) = 2*A134058(n, k) - 1.
From G. C. Greubel, May 03 2021: (Start)
T(n, k) = 4*binomial(n, k) - 2*[n=0] - 1.
Sum_{k=0..n} T(n, k) = 2^(n+2) - (n + 1 + 2*[n=0]) = A095768(n) - 2*[n=0]. (End)