A229163 Number of n X n binary matrices with exactly 4 ones in each row and column, and with rows and columns in lexicographically nondecreasing order.

0, 0, 0, 1, 1, 5, 161, 7776, 626649

Offset

1,6

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-A229164, A000513.

A column of A227061.

Sequence in context: A222628 A287032 A136368 * A322747 A274712 A117068

Adjacent sequences: A229160 A229161 A229162 * A229164 A229165 A229166

Keyword

nonn,more

Author

N. J. A. Sloane, Sep 15 2013

Status

approved