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A067968
Number of binary arrangements on n X n array without adjacent three 1's.
4
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
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
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