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A230702
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Number of (n+3)X(2+3) 0..2 white square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3, and upper left element zero
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1
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8, 28, 244, 800, 6576, 21076, 173428, 554040, 4558536, 14555468, 119758148, 382358832, 3145930352, 10044068932, 82639468964, 263844008200, 2170826159272, 6930820136252, 57024624645332, 182063126310336, 1497958570841456
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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) = 31*a(n-2) -126*a(n-4) +42*a(n-6) +79*a(n-8) -a(n-10) +8*a(n-12)
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EXAMPLE
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Some solutions for n=2
..0..x..0..x..2....0..x..2..x..2....0..x..0..x..0....0..x..2..x..2
..x..1..x..0..x....x..1..x..0..x....x..1..x..1..x....x..1..x..0..x
..0..x..2..x..1....0..x..1..x..2....0..x..2..x..0....1..x..0..x..1
..x..1..x..2..x....x..2..x..1..x....x..2..x..0..x....x..2..x..2..x
..0..x..0..x..1....1..x..0..x..0....1..x..1..x..2....1..x..1..x..1
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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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