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A185514
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Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock singular.
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1
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143, 1489, 12361, 115979, 1058503, 9856209, 91539073, 853020411, 7948563615, 74110312433, 691029158489, 6444134240459, 60095780277207, 560446106259121, 5226693550531025, 48744151344694907, 454588941498687343
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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) - 11*a(n-2) - 154*a(n-3) + 224*a(n-4).
Empirical g.f.: x*(143 - 227*x - 3934*x^2 + 6048*x^3) / (1 - 12*x + 11*x^2 + 154*x^3 - 224*x^4). - Colin Barker, Apr 16 2018
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EXAMPLE
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Some solutions for 5 X 3:
..0..0..2....2..0..1....0..0..2....1..0..2....2..0..0....2..0..0....0..1..2
..0..0..1....2..0..2....2..0..2....1..0..1....1..0..1....2..0..2....0..0..0
..0..0..1....2..0..2....0..0..0....1..0..0....1..0..1....2..0..0....1..2..2
..1..0..0....1..0..1....0..0..2....2..0..1....0..0..0....0..0..1....0..0..0
..1..0..2....0..0..2....0..0..1....1..0..0....1..1..2....0..0..2....1..1..2
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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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