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A304947
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Number of nX3 0..1 arrays with every element unequal to 0, 2, 3, 5 or 7 king-move adjacent elements, with upper left element zero.
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2
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1, 7, 13, 21, 29, 58, 120, 250, 515, 1100, 2302, 4973, 10539, 22512, 48417, 103240, 222483, 476629, 1023567, 2201683, 4721852, 10159934, 21815950, 46884155, 100796318, 216507106, 465528729, 1000276465, 2149938118, 4621346273
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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) +2*a(n-2) -9*a(n-3) -8*a(n-4) +27*a(n-5) -8*a(n-6) -22*a(n-7) +29*a(n-8) -9*a(n-9) -22*a(n-10) +9*a(n-11) +44*a(n-12) -33*a(n-13) -10*a(n-14) +30*a(n-15) -32*a(n-16) +4*a(n-17) +6*a(n-18) for n>19
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EXAMPLE
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Some solutions for n=5
..0..0..0. .0..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0
..1..1..1. .1..0..1. .0..0..0. .1..1..1. .0..0..0. .0..0..0. .1..0..1
..1..1..1. .1..1..0. .0..0..0. .0..0..0. .0..0..0. .1..1..1. .0..1..1
..1..1..1. .1..0..1. .1..1..1. .0..0..0. .0..0..0. .1..1..1. .1..0..1
..0..0..0. .0..1..0. .0..1..0. .0..0..0. .1..1..1. .1..1..1. .0..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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