A229164 Number of n X n binary matrices with exactly 5 ones in each row and column, and with rows and columns in lexicographically nondecreasing order.

0, 0, 0, 0, 1, 1, 8, 1112, 287311

Offset

1,7

References

K. Yordzhev, On an Algorithm for Isomorphism-Free Generations of Combinatorial Objects, International Journal of Emerging Trends & Technology in Computer Science (IJETTCS), Web Site: www.ijettcs.org, Volume 2, Issue 6, November - December 2013, ISSN 2278-6856

Links

Table of n, a(n) for n=1..9.

K. Yordzhev, Fibonacci sequence related to a combinatorial problem on binary matrices, arXiv preprint arXiv:1305.6790, 2013

K. Yordzhev, Semi-canonical binary matrices, arXiv preprint arXiv:1506.04642, 2015

Crossrefs

Cf. A229161-A229163, A000516.

A column of A227061.

Sequence in context: A089672 A279881 A246114 * A357543 A003767 A221084

Adjacent sequences: A229161 A229162 A229163 * A229165 A229166 A229167

Keyword

nonn,more

Author

N. J. A. Sloane, Sep 15 2013

Status

approved