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A183596
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1/6 the number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock containing all three values.
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1
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27, 204, 1479, 10797, 78729, 574185, 4187499, 30539367, 222722937, 1624313781, 11846086563, 86393262903, 630064268913, 4595045605149, 33511572001131, 244399197416799, 1782398262186441, 12998993444433333, 94801388754240819
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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) = 8*a(n-1) - 3*a(n-2) - 16*a(n-3) + 2*a(n-4).
Empirical g.f.: 3*x*(9 - 4*x - 24*x^2 + 3*x^3) / (1 - 8*x + 3*x^2 + 16*x^3 - 2*x^4). - Colin Barker, Mar 30 2018
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EXAMPLE
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Some solutions with a(1,1)=0 for 5 X 3:
..0..2..1....0..2..1....0..0..2....0..0..2....0..2..0....0..2..0....0..1..2
..0..1..0....1..0..1....2..1..1....2..1..0....1..2..1....0..1..0....0..2..0
..1..2..2....1..2..0....1..0..2....0..1..2....2..0..0....1..2..1....1..2..1
..0..1..0....0..2..1....2..0..1....2..0..1....1..2..1....2..0..2....1..0..1
..0..2..2....1..1..0....2..1..2....1..2..1....0..1..0....1..1..2....0..2..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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