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A183332
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Number of n X 4 binary arrays with each 1 adjacent to exactly two 0's.
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1
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3, 23, 66, 247, 899, 3254, 11883, 43207, 157266, 572571, 2084227, 7587166, 27619131, 100540587, 365994058, 1332312171, 4849957923, 17655092138, 64269069107, 233955917683, 851659617442, 3100259701471, 11285741436475, 41082996924906
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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)+2*a(n-2)+9*a(n-3)+14*a(n-4)+20*a(n-5)+9*a(n-6)-4*a(n-7)-24*a(n-8)-46*a(n-9)-43*a(n-10)-35*a(n-11)-16*a(n-12)+6*a(n-13)+11*a(n-14)+8*a(n-15)+7*a(n-16)+2*a(n-17)+a(n-18)+2*a(n-19).
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EXAMPLE
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Some solutions for 8 X 4
..0..1..1..0....0..0..0..1....0..1..0..1....1..0..1..0....0..0..0..1
..1..0..0..0....0..0..0..0....0..1..0..0....0..1..1..0....0..0..0..0
..1..0..0..0....0..0..1..1....0..1..1..0....1..1..0..0....1..1..0..0
..0..0..0..1....1..0..1..0....0..0..1..0....0..0..0..0....0..1..1..1
..0..0..0..1....1..0..1..1....0..0..1..0....0..0..1..1....0..0..0..0
..0..0..0..0....0..0..0..0....1..0..1..1....1..1..1..0....1..1..1..1
..1..1..0..0....1..1..1..1....1..0..0..0....0..0..0..0....0..0..0..0
..0..1..0..0....0..0..0..0....0..0..0..0....0..1..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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