A139016 Number of n X n symmetric binary matrices containing no more than six 1s in any 3 X 3 sub-block.

1, 2, 8, 54, 750, 20314, 1052864, 105578342, 20460453442, 7658537650814, 5538947499948096, 7739159053160945260, 20889681750864696919512, 108933637117589912345519132

Offset

0,2

Links

Table of n, a(n) for n=0..13.

Crossrefs

Sequence in context: A345249 A005440 A183282 * A367753 A377098 A380020

Adjacent sequences: A139013 A139014 A139015 * A139017 A139018 A139019

Keyword

nonn

Author

R. H. Hardin, May 31 2008

Status

approved