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A207023
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Number of nX7 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically
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1
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25, 625, 3025, 9450, 23400, 49925, 95900, 170300, 284475, 452425, 691075, 1020550, 1464450, 2050125, 2808950, 3776600, 4993325, 6504225, 8359525, 10614850, 13331500, 16576725, 20424000, 24953300, 30251375, 36412025, 43536375, 51733150
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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) = (55/24)*n^5 + (75/4)*n^4 + (275/8)*n^3 + (75/4)*n^2 - (295/6)*n.
Empirical G.f.: 25*x*(1+19*x-14*x^2+7*x^3-2*x^4)/(1-x)^6. [Colin Barker, May 22 2012]
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EXAMPLE
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Some solutions for n=4
..0..0..1..0..1..0..1....0..1..0..0..1..0..0....1..0..0..1..0..1..0
..0..1..0..1..0..0..1....1..0..1..0..1..0..0....0..1..0..0..1..0..0
..0..1..0..1..0..0..1....1..0..1..0..1..0..0....0..1..0..0..1..0..0
..0..1..0..1..0..0..1....1..0..1..0..1..0..0....0..1..0..0..1..0..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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