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.

A129688 A129686 * A128174.

Original entry on oeis.org

1, 0, 1, 2, 0, 1, 0, 2, 0, 1, 2, 0, 2, 0, 1, 0, 2, 0, 2, 0, 1, 2, 0, 2, 0, 2, 0, 1, 0, 2, 0, 2, 0, 2, 0, 1, 2, 0, 2, 0, 2, 0, 2, 0, 1, 0, 2, 0, 2, 0, 2, 0, 2, 0, 1
Offset: 1

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Author

Gary W. Adamson, Apr 28 2007

Keywords

Comments

Resulting triangle has (1, 0, 2, 0, 2, 0, 2, ...) in every column.
Row sums = A109613: (1, 1, 3, 3, 5, 5, ...).

Examples

			First few rows of the triangle:
  1;
  0, 1;
  2, 0, 1;
  0, 2, 0, 1;
  2, 0, 2, 0, 1;
  ...
		

Crossrefs

Programs

  • Mathematica
    T[n_, k_] := If[k == n, 1, If[EvenQ[n + k], 2, 0]];
    Table[T[n, k], {n, 1, 10}, {k, 1, n}] // Flatten (* Jean-François Alcover, Jul 10 2019 *)

Formula

A129686 * A128174 as infinite lower triangular matrices.