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.

A057149 Triangle T(n,k) of n X n binary matrices with k ones, with no zero rows or columns, up to row and column permutation.

Original entry on oeis.org

0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 2, 5, 4, 3, 1, 1, 0, 0, 0, 0, 1, 2, 11, 21, 34, 33, 33, 19, 14, 6, 3, 1, 1, 0, 0, 0, 0, 0, 1, 2, 14, 49, 131, 248, 410, 531, 601, 566, 474, 336, 222, 124, 67, 32, 16, 6, 3, 1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 15, 69, 288, 840, 2144, 4488, 8317, 13160
Offset: 1

Views

Author

Vladeta Jovovic, Aug 14 2000

Keywords

Comments

Row sums give A054976.

Examples

			[0,1], [0,0,1,1,1], [0,0,0,1,2,5,4,3,1,1],...;
T(4,6)=11, i.e. there are 11 4 X 4 binary matrices with 6 ones, with no zero rows or columns, up to row and column permutation:
[0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1]
[0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 1 0]
[0 0 0 1] [0 0 1 0] [0 0 1 0] [0 0 1 1] [0 1 1 0] [0 0 1 1]
[1 1 1 0] [1 1 0 1] [1 1 1 0] [1 1 0 0] [1 0 1 0] [1 1 0 0]
and
[0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1] [0 0 0 1]
[0 0 1 0] [0 0 1 0] [0 0 1 0] [0 0 1 0] [0 0 1 0]
[0 1 0 0] [0 1 0 1] [0 1 0 1] [0 1 0 1] [1 1 0 0]
[1 0 1 1] [1 0 0 1] [1 0 1 0] [1 1 0 0] [1 1 0 0].
		

Crossrefs