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A183776
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Half the number of (n+1) X 4 binary arrays with no 2 X 2 subblock having exactly 2 ones.
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1
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33, 161, 730, 3435, 15887, 74148, 344483, 1604473, 7462786, 34738575, 161631659, 752241404, 3500410439, 16290047469, 75805472562, 352771994195, 1641641366551, 7639557462868, 35551227927131, 165441007206577, 769893052530306
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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) = 2*a(n-1) + 18*a(n-2) - 13*a(n-3) - 70*a(n-4) + 24*a(n-5) + 64*a(n-6).
Empirical g.f.: x*(33 + 95*x - 186*x^2 - 494*x^3 + 280*x^4 + 512*x^5) / ((1 + 2*x)*(1 - 4*x - 10*x^2 + 33*x^3 + 4*x^4 - 32*x^5)). - Colin Barker, Apr 04 2018
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EXAMPLE
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Some solutions with a(1,1)=0 for 3 X 4:
..0..1..1..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..0..1
..0..0..1..0....0..0..0..0....0..1..0..1....0..0..1..0....0..0..0..0
..0..0..0..0....0..1..0..0....0..0..0..0....1..0..0..0....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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