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A304305
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Number of n X 3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero.
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1
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4, 23, 77, 261, 918, 3270, 11739, 42286, 152593, 551277, 1992676, 7204835, 26054060, 94223657, 340770353, 1232459982, 4457471732, 16121551990, 58307765439, 210885454206, 762723638858, 2758595178785, 9977203623515, 36085252551736
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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) -6*a(n-3) -11*a(n-4) +2*a(n-5) +14*a(n-6) -6*a(n-7) -7*a(n-8) +15*a(n-9) +22*a(n-10) -6*a(n-11) -7*a(n-12) +a(n-13) +3*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..0. .0..0..0. .0..0..1. .0..1..0. .0..1..1. .0..1..1. .0..1..0
..1..1..1. .1..0..1. .0..0..0. .1..0..1. .0..0..1. .0..1..0. .1..1..1
..1..1..1. .0..0..0. .0..0..0. .1..1..0. .0..0..0. .1..0..0. .0..1..1
..0..1..1. .0..0..0. .0..1..1. .0..0..0. .0..0..0. .0..1..0. .0..0..1
..1..1..0. .0..0..1. .1..1..0. .0..0..1. .0..0..1. .1..0..1. .1..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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