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A304889
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Number of nX3 0..1 arrays with every element unequal to 0, 2, 3, 4 or 7 king-move adjacent elements, with upper left element zero.
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2
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1, 8, 11, 40, 94, 291, 776, 2269, 6275, 17985, 50548, 143589, 405620, 1149709, 3252139, 9211083, 26070305, 73816122, 208963020, 591618663, 1674877081, 4741816884, 13424434567, 38006135552, 107599067346, 304624934972
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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) = 3*a(n-1) +3*a(n-2) -7*a(n-3) -8*a(n-4) -8*a(n-5) +26*a(n-6) -13*a(n-7) -16*a(n-8) +76*a(n-9) -33*a(n-10) -22*a(n-11) +27*a(n-12) -23*a(n-13) +11*a(n-14) +7*a(n-15) -5*a(n-16) +5*a(n-17) -2*a(n-18) -2*a(n-19) for n>20
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EXAMPLE
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Some solutions for n=5
..0..1..1. .0..1..0. .0..1..0. .0..0..0. .0..0..1. .0..1..0. .0..1..0
..1..0..0. .0..1..0. .1..0..1. .0..0..0. .0..0..1. .1..1..1. .1..1..1
..1..0..0. .1..1..1. .0..0..0. .0..0..0. .0..0..1. .0..1..0. .0..1..0
..1..0..0. .0..1..0. .1..0..1. .1..1..1. .0..0..1. .1..0..0. .0..0..1
..0..1..1. .0..1..0. .1..0..1. .1..1..1. .0..0..1. .1..0..1. .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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