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A219143
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Unchanging value maps: number of 2 X n binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 2 X n array.
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2
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1, 6, 18, 39, 96, 225, 543, 1293, 3096, 7392, 17673, 42228, 100929, 241197, 576441, 1377606, 3292314, 7868187, 18803964, 44939013, 107398431, 256668285, 613403916, 1465955712, 3503443917, 8372776200, 20009848437, 47820940581, 114285841233
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OFFSET
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1,2
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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) + a(n-2) - a(n-3) + 2*a(n-4) for n>5.
Empirical g.f.: x*(1 + 4*x + 5*x^2 - 2*x^3 + 4*x^4) / (1 - 2*x - x^2 + x^3 - 2*x^4). - Colin Barker, Mar 11 2018
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EXAMPLE
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Some solutions for n=3:
..1..0..0....0..0..0....0..0..1....0..0..1....0..0..1....1..0..1....1..1..1
..0..0..1....1..0..0....1..0..0....1..0..1....0..0..0....0..0..0....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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