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A208040
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Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 0 and 1 0 1 vertically.
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1
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9, 81, 279, 961, 4743, 23409, 100215, 429025, 1942075, 8791225, 38933415, 172423161, 770225067, 3440643649, 15317395695, 68191488225, 303989603715, 1355149763881, 6037892299063, 26901929503849, 119887169037291
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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) = 2*a(n-1) +24*a(n-3) +117*a(n-4) +10*a(n-5) +88*a(n-6) -540*a(n-7) -2784*a(n-8) -648*a(n-9) +880*a(n-10) +2080*a(n-11) +11700*a(n-12) +4200*a(n-13) +2000*a(n-15) -10000*a(n-16).
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EXAMPLE
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Some solutions for n=4
..1..1..0..1....1..0..0..1....1..0..0..1....0..1..1..0....0..1..1..0
..0..1..1..1....1..0..1..1....1..0..1..1....0..1..1..1....1..0..0..1
..0..0..1..1....0..1..1..1....0..1..1..0....1..0..0..1....1..0..0..1
..1..0..0..1....0..0..1..1....0..1..1..0....1..0..0..1....1..1..1..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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