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.

A139038 Triangle read by rows: T(n,m) = A000931(m+6) if m <= floor(n/2), A000931(n+6-m) otherwise, for 0 <= m <= n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 3, 2, 2, 1, 1, 1, 1, 2, 2, 3, 3, 2, 2, 1, 1, 1, 1, 2, 2, 3, 4, 3, 2, 2, 1
Offset: 0

Views

Author

Roger L. Bagula and Gary W. Adamson, May 31 2008

Keywords

Comments

The Padovan sequence is pushed back to a(-1)=1, so that the triangle is not almost all ones.

Examples

			The triangle begins:
  1;
  1, 1;
  1, 1, 1;,
  1, 1, 1, 1;
  1, 1, 2, 1, 1;
  1, 1, 2, 2, 1, 1;
  1, 1, 2, 2, 2, 1, 1;
  1, 1, 2, 2, 2, 2, 1, 1;
  1, 1, 2, 2, 3, 2, 2, 1, 1;
  1, 1, 2, 2, 3, 3, 2, 2, 1, 1;
  1, 1, 2, 2, 3, 4, 3, 2, 2, 1, 1;
  ...
		

Crossrefs

Programs

  • Mathematica
    a[-1] = 1; a[0] = 1; a[1] = 1; a[n_] := a[n] = a[n - 2] + a[n - 3]; (* Padovan : A000931 *)
    Table[If[m <= Floor[n/2], a[m], a[n - m]], {n, 0, 10}, {m, 0, n}]

Extensions

Edited by N. J. A. Sloane, Feb 28 2009
Non-ASCII characters in %t line corrected by Wouter Meeussen, Feb 10 2013
Definition corrected and offset changed by Georg Fischer, May 16 2024