A067968 Number of binary arrangements on n X n array without adjacent three 1's.

1, 2, 11, 163, 6547, 720417, 216173426, 177509416175, 398239490006383, 2441922679051541299, 40923800121824894177005, 1874434223405139511637099884, 234647514833189124245764389957097, 80281172893810827268371440460572492150

Offset: 0

Author

R. H. Hardin, Feb 02 2002

Keywords

• nonn

References

• Steven R. Finch, Mathematical Constants, Cambridge, 2003, pp. 342-349.

Links

• Steven R. Finch, Hard Square Entropy Constant [Broken link]
• Steven R. Finch, Hard Square Entropy Constant [From the Wayback machine]

Crossrefs

Adjacent three in a row or column gives A050974.

Extensions

a(13) from Sean A. Irvine, Jan 15 2024

a(0)=1 prepended by Alois P. Heinz, Sep 26 2024