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A303723
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Number of n X 4 0..1 arrays with every element unequal to 0, 1, 2 or 3 king-move adjacent elements, with upper left element zero.
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1
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8, 49, 46, 84, 133, 221, 406, 743, 1327, 2396, 4385, 8003, 14556, 26527, 48421, 88330, 161061, 293777, 535950, 977643, 1783259, 3252908, 5933861, 10824167, 19744652, 36017043, 65700297, 119846482, 218616585, 398787421, 727444438, 1326960543
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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) = a(n-1) +a(n-2) +a(n-3) +a(n-4) -a(n-5) -2*a(n-6) for n>8.
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EXAMPLE
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Some solutions for n=5
..0..1..1..1. .0..0..0..0. .0..1..1..1. .0..1..1..1. .0..1..1..1
..0..1..1..1. .0..0..0..0. .1..1..1..0. .1..1..1..1. .1..1..1..1
..0..1..1..1. .0..0..0..0. .1..1..0..0. .1..1..1..0. .1..1..1..1
..0..1..1..1. .0..0..0..1. .1..0..0..0. .1..1..0..0. .1..1..1..0
..0..1..1..0. .1..0..1..1. .0..0..0..0. .1..0..0..0. .0..1..0..0
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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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