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A269216
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Number of 3Xn 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three exactly once.
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1
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0, 1152, 18048, 308544, 4744704, 70371048, 1012764384, 14272781904, 197924795136, 2710127012280, 36731155605600, 493646491209600, 6587572246924800, 87381895621488648, 1153101183028855008
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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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FORMULA
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Empirical: a(n) = 24*a(n-1) -130*a(n-2) -248*a(n-3) +935*a(n-4) +272*a(n-5) -1768*a(n-6) +960*a(n-7) -144*a(n-8)
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EXAMPLE
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Some solutions for n=3
..2..3..1. .0..2..3. .0..0..0. .1..3..1. .2..2..2. .3..2..2. .0..1..0
..3..1..1. .0..0..2. .2..2..3. .3..3..1. .1..0..0. .0..0..0. .1..0..2
..0..1..3. .0..0..2. .2..2..0. .2..1..1. .0..0..2. .0..1..0. .0..0..2
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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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