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A145835
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Number of compositions of the n X n grid graph
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2
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1, 12, 1434, 1691690, 19719299768, 2271230282824746, 2584855762327078145444, 29068227444022728740767607050, 3230042572278849047360048508956727420, 3546545075986984198328715750838554116235343894
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OFFSET
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1,2
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COMMENTS
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The number of compositions of the n X n grid graph is the number of partitions of an n X n square into regions of orthogonally connected unit squares.
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LINKS
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EXAMPLE
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For n=2 the a(2)=12 partitions of a 2x2 square are: 1 partition into a single 2x2 region; 4 partitions into a 3-square 'L' shape and an isolated corner; 2 partitions into 2 1x2 bricks; 4 partitions into a 1x2 brick and 2 isolated squares; and 1 partition into 4 isolated squares.
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CROSSREFS
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KEYWORD
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hard,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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