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

0,2

References

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

Links

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

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.

Sequence in context: A288560 A318173 A349639 * A295269 A197336 A013050

Adjacent sequences: A067965 A067966 A067967 * A067969 A067970 A067971

Keyword

nonn

Author

R. H. Hardin, Feb 02 2002

Extensions

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

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

Status

approved