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A269038
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Number of 4Xn 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once.
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1
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0, 504, 2136, 18384, 115656, 785124, 4998648, 31834476, 198736752, 1231177296, 7552688064, 46020487500, 278641166280, 1678349335044, 10062618187272, 60089435895360, 357550261665528, 2120806295463156, 12543856834626072
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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) = 6*a(n-1) +23*a(n-2) -102*a(n-3) -288*a(n-4) +250*a(n-5) +787*a(n-6) -238*a(n-7) -741*a(n-8) +124*a(n-9) +196*a(n-10) -16*a(n-11) -16*a(n-12) for n>14
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EXAMPLE
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Some solutions for n=4
..0..1..0..1. .2..2..2..1. .2..2..2..2. .1..0..0..2. .2..2..1..2
..2..1..2..1. .2..2..2..2. .1..2..2..1. .1..0..1..0. .2..2..2..2
..0..1..0..1. .2..1..2..1. .1..2..1..2. .0..0..1..0. .2..2..2..2
..0..0..2..1. .0..2..2..1. .1..2..1..2. .1..0..1..0. .2..2..1..1
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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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