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A303795
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Number of nX3 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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1
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4, 12, 17, 30, 70, 121, 221, 421, 800, 1511, 2832, 5340, 10089, 19009, 35825, 67558, 127375, 240150, 452774, 853653, 1609501, 3034561, 5721352, 10787091, 20338064, 38345504, 72296881, 136309037, 256998009, 484545858, 913566127, 1722443986
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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) +2*a(n-3) -a(n-5) -2*a(n-6) -2*a(n-7) for n>10
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EXAMPLE
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Some solutions for n=5
..0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0. .0..1..0. .0..1..1
..0..0..1. .0..1..1. .0..0..0. .0..0..0. .1..0..1. .0..0..1. .0..1..1
..0..0..0. .1..1..1. .0..0..0. .0..0..0. .1..0..1. .0..0..0. .1..1..1
..0..0..0. .1..1..1. .0..0..0. .0..0..0. .0..0..0. .1..0..0. .1..1..1
..1..1..0. .1..0..0. .1..1..0. .0..1..1. .0..0..0. .1..0..0. .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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