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A305218
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Number of nX3 0..1 arrays with every element unequal to 2, 3, 5, 6 or 7 king-move adjacent elements, with upper left element zero.
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2
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0, 4, 8, 15, 31, 92, 264, 784, 2378, 7342, 22596, 69617, 214983, 664217, 2052307, 6342935, 19606074, 60603932, 187335711, 579091828, 1790098137, 5533594957, 17105617402, 52877461311, 163456660240, 505283076436, 1561949355656
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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) +5*a(n-2) -12*a(n-4) -15*a(n-5) +3*a(n-6) +30*a(n-7) +14*a(n-8) -40*a(n-9) -44*a(n-10) +23*a(n-11) +66*a(n-12) +22*a(n-13) -15*a(n-14) -6*a(n-15) for n>18
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EXAMPLE
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Some solutions for n=5
..0..0..1. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0. .0..1..0
..1..1..0. .1..1..1. .1..1..0. .1..1..0. .1..0..1. .1..1..0. .1..1..1
..1..0..0. .1..0..1. .0..0..1. .0..0..1. .1..0..1. .1..0..0. .1..0..1
..0..1..1. .1..0..1. .0..1..1. .0..1..1. .1..0..1. .0..1..1. .0..0..1
..0..1..0. .0..1..0. .1..0..0. .0..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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