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A198709
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Number of n X n 0..3 arrays with values 0..3 introduced in row major order and no element equal to any horizontal or vertical neighbor
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2
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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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EXAMPLE
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Some solutions with all values from 0 to 3 for n=4
..0..1..0..1....0..1..0..2....0..1..0..1....0..1..0..2....0..1..2..0
..1..2..1..3....1..2..1..3....1..0..2..3....2..3..2..3....1..0..3..1
..2..1..3..2....2..1..3..2....2..3..1..2....1..2..0..1....0..3..1..2
..1..3..1..0....1..2..0..1....3..0..2..1....2..0..3..0....2..1..2..3
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MATHEMATICA
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A198715 = Import["https://oeis.org/A198715/b198715.txt", "Table"][[All, 2]];
a[n_] := A198715[[2 n^2 - 2 n + 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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