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A207270
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Number of 3Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically
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2
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6, 36, 82, 217, 499, 1014, 2141, 4188, 8150, 15670, 29517, 55523, 103348, 191593, 353916, 651316, 1196664, 2193747, 4017137, 7347906, 13429145, 24530862, 44784850, 81739060, 149141623, 272067741, 496250336, 905026713, 1650411906
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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) = a(n-1) +4*a(n-2) +2*a(n-3) -12*a(n-4) -9*a(n-5) +6*a(n-6) +20*a(n-7) +6*a(n-8) -2*a(n-9) -16*a(n-10) -12*a(n-11) -4*a(n-12) +14*a(n-13) +9*a(n-14) +a(n-15) -6*a(n-16) -2*a(n-17) +a(n-19)
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EXAMPLE
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Some solutions for n=4
..1..0..1..0....1..1..1..0....0..0..1..0....1..0..1..0....0..0..1..0
..0..0..1..0....0..0..1..0....1..0..1..0....0..0..1..0....0..1..0..0
..0..1..0..1....0..0..1..0....0..1..0..1....0..0..1..0....1..0..0..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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