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A067968 Number of binary arrangements on n X n array without adjacent three 1's. 4
2, 11, 163, 6547, 720417, 216173426, 177509416175, 398239490006383, 2441922679051541299, 40923800121824894177005, 1874434223405139511637099884, 234647514833189124245764389957097 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

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

LINKS

Table of n, a(n) for n=1..12.

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

STATUS

approved

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Last modified December 5 12:24 EST 2021. Contains 349557 sequences. (Running on oeis4.)