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A221588
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Equals one maps: number of n X 3 binary arrays indicating the locations of corresponding elements equal to exactly one of their king-move neighbors in a random 0..3 n X 3 array.
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1
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4, 40, 418, 3760, 31416, 256736, 2075520, 16690688, 133871616, 1072357376, 8584396800, 68697325568, 549667209216, 4397692092416, 35182954414080, 281469306011648, 2251777130889216, 18014307778297856, 144114825151119360
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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) = 12*a(n-1) -32*a(n-2) for n>6.
G.f.: 2*x*(2 - 4*x + 33*x^2 + 12*x^3 - 164*x^4 + 32*x^5) / ((1 - 4*x)*(1 - 8*x)).
a(n) = 8^n - 169*2^(2*n-7) for n>4.
(End)
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EXAMPLE
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Some solutions for n=3:
..0..1..0....0..1..0....1..0..1....1..1..1....0..1..0....0..1..0....1..1..1
..0..1..0....0..0..1....1..0..0....0..1..0....1..0..0....0..0..0....1..1..1
..0..1..1....1..1..1....0..1..0....0..0..1....0..1..1....1..1..1....0..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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