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A183665
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Number of (n+1) X 3 0..6 arrays with every 2 X 2 subblock summing to 12.
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1
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1225, 5215, 24745, 126223, 678265, 3791935, 21874825, 129463663, 782782105, 4819857055, 30146536105, 191148081103, 1226597365945, 7954555064575, 52068989200585, 343658085034543, 2284795961645785, 15288911173702495
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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) = 28*a(n-1) - 322*a(n-2) + 1960*a(n-3) - 6769*a(n-4) + 13132*a(n-5) - 13068*a(n-6) + 5040*a(n-7).
Empirical g.f.: x*(1225 - 29085*x + 273175*x^2 - 1288407*x^3 + 3182536*x^4 - 3842244*x^5 + 1728720*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)*(1 - 7*x)). - Colin Barker, Apr 02 2018
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EXAMPLE
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Some solutions for 5 X 3:
..2..6..2....1..3..2....4..3..4....0..4..0....3..3..3....3..2..2....0..6..2
..4..0..4....4..4..3....3..2..3....3..5..3....6..0..6....3..4..4....2..4..0
..6..2..6....2..2..3....3..4..3....3..1..3....1..5..1....5..0..4....2..4..4
..1..3..1....5..3..4....2..3..2....6..2..6....2..4..2....5..2..6....6..0..4
..5..3..5....2..2..3....3..4..3....0..4..0....1..5..1....3..2..2....4..2..6
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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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