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.

A128140 A128132 * A004736.

Original entry on oeis.org

1, 3, 2, 7, 5, 3, 13, 10, 7, 4, 21, 17, 13, 9, 5, 31, 26, 21, 16, 11, 6, 43, 37, 31, 25, 19, 13, 7, 57, 50, 43, 36, 29, 22, 15, 8, 73, 65, 57, 49, 41, 33, 25, 17, 9, 91, 82, 73, 64, 55, 46, 37, 28, 19, 10
Offset: 1

Views

Author

Gary W. Adamson, Feb 16 2007

Keywords

Comments

Row sums = A006003, starting (1, 5, 15, 34, 65, 111, ...). Left border = A002061: (1, 3, 7, 13, 21, 31, 43, ...) A128139 = A004736 * A128132

Examples

			First few rows of the triangle:
   1;
   3,  2;
   7,  5,  3;
  13, 10,  7,  4;
  21, 17, 13,  9,  5;
  31, 26, 21, 16, 11,  6;
  43, 37, 31, 25, 19, 13,  7;
  ...
		

Crossrefs

Formula

A128132 * A004736 as infinite lower triangular matrices.