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A207897
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Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 0 and 1 1 1 vertically
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1
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10, 100, 292, 870, 2446, 6952, 20168, 57838, 164914, 473632, 1360740, 3896086, 11165294, 32038792, 91859552, 263284722, 754983634, 2164966616, 6206791972, 17795617610, 51026354878, 146302277604, 419468202104, 1202710746958
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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) = 3*a(n-2) +10*a(n-3) +18*a(n-4) -2*a(n-5) -22*a(n-6) -7*a(n-7) -12*a(n-9) -8*a(n-10) -6*a(n-11) -6*a(n-12) -3*a(n-13) -a(n-14) +3*a(n-15) +a(n-16) -a(n-17) for n>18
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EXAMPLE
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Some solutions for n=4
..1..0..0..1....0..1..1..0....1..0..0..1....1..1..0..0....0..1..1..0
..1..1..0..0....0..1..1..1....0..1..1..0....0..0..1..1....1..1..0..0
..0..1..1..0....1..0..0..1....1..0..0..1....1..1..0..0....0..0..1..1
..0..0..1..1....1..1..1..0....1..1..1..1....1..0..0..1....1..1..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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