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A145757
Number of n X n binary arrays with all ones connected only either three adjacent vertically or three adjacent horizontally.
0
1, 1, 9, 45, 476, 6933, 199238, 8764691, 657200985, 80295518797, 16444907566268, 5549422397331424, 3112070848837147326
OFFSET
1,3
CROSSREFS
Sequence in context: A001556 A230063 A009432 * A058824 A244302 A177742
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 17 2008
STATUS
approved