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A303794
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Number of nX2 0..1 arrays with every element unequal to 0, 1, 2 or 4 king-move adjacent elements, with upper left element zero.
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8
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2, 4, 12, 24, 64, 184, 432, 1088, 2944, 7360, 18496, 48384, 123392, 312320, 804864, 2061824, 5248000, 13449216, 34455552, 87961600, 225038336, 576143360, 1472741376, 3766452224, 9638051840, 24648581120, 63037702144, 161266270208
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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) = 2*a(n-1) +8*a(n-3) -8*a(n-4) -8*a(n-5) for n>6
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EXAMPLE
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Some solutions for n=5
..0..1. .0..1. .0..1. .0..0. .0..0. .0..0. .0..1. .0..0. .0..1. .0..0
..1..0. .1..0. .0..1. .0..0. .1..0. .0..1. .1..0. .1..1. .1..0. .1..1
..1..1. .1..1. .0..0. .0..1. .1..0. .0..1. .0..0. .1..1. .0..0. .1..1
..1..1. .0..1. .0..0. .0..1. .1..1. .0..0. .1..0. .0..1. .1..0. .1..0
..0..0. .1..0. .0..0. .1..1. .1..1. .0..0. .1..0. .0..1. .0..1. .1..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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