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A183785
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Half the number of (n+1) X 3 0..2 arrays with no 2 X 2 subblock having sum 4.
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1
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216, 3552, 57966, 948164, 15497634, 253372446, 4142036148, 67714639662, 1106996131802, 18097205612196, 295853182740306, 4836611736951630, 79068975444380772, 1292620478037357518, 21131773136239117962
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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) = 12*a(n-1) + 90*a(n-2) - 279*a(n-3) - 618*a(n-4) + 2092*a(n-5) - 1344*a(n-6).
Empirical g.f.: 2*x*(108 + 480*x - 2049*x^2 - 3422*x^3 + 13611*x^4 - 9072*x^5) / (1 - 12*x - 90*x^2 + 279*x^3 + 618*x^4 - 2092*x^5 + 1344*x^6). - Colin Barker, Apr 04 2018
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EXAMPLE
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Some solutions for 5 X 3:
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..1....0..0..0
..1..1..2....1..2..1....1..2..1....1..1..1....1..0..2....0..0..0....2..1..0
..1..0..0....2..1..2....2..2..1....2..1..2....1..1..0....2..1..0....0..0..1
..0..0..1....0..2..0....1..2..2....0..2..0....1..0..1....2..0..1....2..1..1
..1..1..0....1..0..1....2..1..1....1..2..1....0..0..1....0..1..0....2..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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