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A304137
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Number of nX4 0..1 arrays with every element unequal to 0, 2, 3 or 6 king-move adjacent elements, with upper left element zero.
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1
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1, 13, 9, 11, 20, 17, 25, 62, 59, 93, 220, 237, 381, 830, 991, 1601, 3236, 4185, 6769, 12894, 17715, 28661, 52204, 75029, 121397, 213918, 317815, 514233, 884532, 1346273, 2178313, 3682046, 5702891, 9227469, 15402748, 24157821, 39088173
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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) +2*a(n-3) -6*a(n-4) +3*a(n-6) for n>10
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EXAMPLE
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Some solutions for n=5
..0..0..1..1. .0..1..1..1. .0..1..0..0. .0..0..1..0. .0..0..1..0
..0..0..1..1. .0..1..1..1. .1..1..0..0. .1..1..0..1. .0..0..1..1
..0..0..1..1. .0..1..1..1. .0..0..0..0. .1..1..1..1. .0..0..0..0
..0..0..1..1. .0..1..1..1. .0..0..1..1. .1..1..0..1. .1..1..0..0
..0..0..1..1. .0..1..1..1. .0..0..1..0. .0..0..1..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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