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A220724
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Number of ways to reciprocally link elements of an n X 7 array either to themselves or to exactly two horizontal, diagonal or antidiagonal neighbors.
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1
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1, 717, 114900, 21914482, 4067687187, 759141297226, 141539684300104, 26392338517041335, 4921196474806555320, 917624537292862421240, 171103547699638196272026, 31904579896557581955181967
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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Some solutions for n=3 0=self 1=nw 3=ne 4=w 6=e 7=sw 9=se (reciprocal directions total 10)
.00.67.47.00.00.79.00...00.67.49.00.67.46.47...00.67.47.69.46.46.47
.36.34.67.49.37.79.17...36.46.47.13.00.39.00...39.37.00.00.17.36.47
.00.36.46.34.13.36.14...00.36.46.46.46.46.14...36.14.00.36.46.34.00
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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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