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A221589
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Equals one maps: number of n X 4 binary arrays indicating the locations of corresponding elements equal to exactly one of their king-move neighbors in a random 0..3 n X 4 array.
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1
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8, 180, 3760, 64324, 1043774, 16758008, 268358624, 4294659968, 68718247424, 1099506710528, 17592166375424, 281474898034688, 4503599312666624, 72057592779112448, 1152921499571585024, 18446744053568503808
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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) = 20*a(n-1) -64*a(n-2) for n>6.
G.f.: 2*x*(4 + 10*x + 336*x^2 + 322*x^3 - 1033*x^4 - 368*x^5) / ((1 - 4*x)*(1 - 16*x)).
a(n) = 16^n - 2401*2^(2*n-9) for n>4.
(End)
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EXAMPLE
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Some solutions for n=3.
..1..0..0..1....0..0..0..0....0..0..0..1....0..0..1..1....0..0..0..1
..0..0..1..1....0..0..0..1....1..0..0..1....0..1..1..1....1..1..1..0
..0..1..1..0....0..1..0..0....0..1..1..0....0..0..0..1....1..0..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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