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A318063
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Number of nX3 0..1 arrays with every element unequal to 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
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1
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1, 18, 98, 649, 4003, 25106, 156846, 980960, 6133497, 38352691, 239814461, 1499536299, 9376441731, 58629916469, 366606748842, 2292353789490, 14333849236061, 89628064900328, 560434945455139, 3504341284919904
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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) = 5*a(n-1) +9*a(n-2) -7*a(n-3) -3*a(n-4) +8*a(n-5) -2*a(n-6) -9*a(n-7) -2*a(n-8) -a(n-9) +2*a(n-11) for n>12
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EXAMPLE
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Some solutions for n=5
..0..1..1. .0..1..0. .0..1..1. .0..0..1. .0..0..1. .0..1..0. .0..1..0
..0..1..0. .1..0..1. .0..0..0. .1..0..1. .1..0..1. .0..1..1. .1..0..0
..0..1..0. .1..0..0. .1..0..1. .0..0..1. .0..0..1. .1..1..0. .0..1..0
..0..1..1. .0..0..0. .1..0..0. .1..0..0. .0..0..0. .0..0..0. .1..1..1
..0..0..0. .0..1..0. .0..1..1. .0..1..0. .1..1..0. .1..0..1. .0..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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