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A223372
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3X3 square grid graph coloring a rectangular array: number of nX1 0..8 arrays where 0..8 label nodes of the square grid graph and every array movement to a horizontal or vertical neighbor moves along an edge of this graph
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1
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9, 24, 68, 192, 544, 1536, 4352, 12288, 34816, 98304, 278528, 786432, 2228224, 6291456, 17825792, 50331648, 142606336, 402653184, 1140850688, 3221225472, 9126805504, 25769803776, 73014444032, 206158430208, 584115552256
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 8*a(n-2) for n>3
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EXAMPLE
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Some solutions for n=3
..7....3....4....5....2....7....6....2....6....3....5....6....7....7....1....1
..4....4....1....4....5....4....7....5....3....6....8....7....4....8....4....2
..7....3....0....3....2....1....4....4....0....7....5....6....3....7....1....1
Vertex neighbors:
0 -> 1 3
1 -> 0 2 4
2 -> 1 5
3 -> 0 4 6
4 -> 3 1 5 7
5 -> 4 2 8
6 -> 3 7
7 -> 6 4 8
8 -> 7 5
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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