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A302225
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Number of 2Xn 0..1 arrays with every element equal to 1, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
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4
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0, 3, 14, 45, 146, 537, 1934, 6861, 24386, 86913, 309638, 1102677, 3927050, 13986633, 49814510, 177416541, 631877618, 2250466449, 8015156630, 28546401765, 101669514458, 362101348953, 1289643083966, 4593131945709, 16358681988674
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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) = 2*a(n-1) +3*a(n-2) +6*a(n-3) +10*a(n-4) +4*a(n-5) for n>6
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EXAMPLE
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Some solutions for n=5
..0..0..0..1..0. .0..0..1..1..0. .0..0..0..1..0. .0..0..0..1..1
..0..1..1..0..1. .0..1..0..0..0. .0..1..1..0..0. .0..1..1..0..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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