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A305771
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Number of n X 3 0..1 arrays with every element unequal to 0, 1, 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.
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1
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4, 23, 81, 292, 1096, 4172, 15953, 61111, 234288, 898583, 3447045, 13224257, 50735544, 194653051, 746816146, 2865285427, 10993168588, 42177249636, 161820597240, 620853918472, 2382018289657, 9139044147504, 35063597098216
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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) = 4*a(n-1) +a(n-2) -a(n-3) -20*a(n-4) -8*a(n-5) +26*a(n-6) +14*a(n-7) -12*a(n-8) +11*a(n-9) +23*a(n-10) -8*a(n-11) -24*a(n-12) -10*a(n-13) +7*a(n-14) -10*a(n-15) -8*a(n-16).
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EXAMPLE
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Some solutions for n=5
..0..0..1. .0..1..1. .0..1..1. .0..1..1. .0..1..1. .0..1..0. .0..0..1
..0..1..0. .1..0..1. .0..1..0. .1..0..0. .1..0..1. .1..1..1. .0..0..0
..0..0..0. .1..1..1. .1..0..0. .1..0..1. .0..1..0. .0..1..1. .0..0..1
..1..0..0. .0..0..1. .0..1..0. .0..1..1. .0..1..0. .0..0..1. .1..0..0
..0..0..0. .1..0..0. .0..1..1. .0..0..0. .1..0..1. .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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