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.

A128220 Triangle, A127701 * A000012.

Original entry on oeis.org

1, 3, 2, 4, 4, 3, 5, 5, 5, 4, 6, 6, 6, 6, 5, 7, 7, 7, 7, 7, 6, 8, 8, 8, 8, 8, 8, 7, 9, 9, 9, 9, 9, 9, 9, 8, 10, 10, 10, 10, 10, 10, 10, 10, 9, 11, 11, 11, 11, 11, 11, 11, 11, 11, 10
Offset: 1

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Author

Gary W. Adamson, Feb 19 2007

Keywords

Comments

Row sums = A028387: (1, 5, 11, 19, 29, 41, 55, ...) A000012 * A127701 = A128219.

Examples

			First few rows of the triangle:
  1;
  3, 2;
  4, 4, 3;
  5, 5, 5, 4;
  6, 6, 6, 6, 5;
  7, 7, 7, 7, 7, 6;
  ...
		

Crossrefs

Formula

A127701 * A000012 as infinite lower triangular matrices. Triangle read by rows: a(1) = 1; n-th row = (n-1) terms of (n+1) followed by "n".