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A229582
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Number of defective 3-colorings of an n X 4 0..2 array connected horizontally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order.
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1
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6, 116, 1620, 19764, 224532, 2440692, 25745364, 265720500, 2697594516, 27033340788, 268094978388, 2636009007156, 25732468879380, 249667710249204, 2409688805255892, 23151313964420532, 221538858133842324
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OFFSET
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1,1
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..210
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FORMULA
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Empirical: a(n) = 18*a(n-1) - 81*a(n-2) for n>3.
Conjectures from Colin Barker, Sep 19 2018: (Start)
G.f.: 2*x*(3 + 4*x + 9*x^2) / (1 - 9*x)^2.
a(n) = 4 * 9^(n - 2) * (16*n - 3) for n>1.
(End)
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EXAMPLE
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Some solutions for n=3:
..0..1..0..1....0..1..1..2....0..1..0..2....0..1..2..1....0..1..2..0
..0..2..1..2....0..2..0..2....0..1..0..2....0..1..0..1....1..0..1..0
..1..0..1..0....0..2..1..0....1..2..1..2....1..2..0..2....1..2..1..0
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CROSSREFS
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Column 4 of A229586.
Sequence in context: A278752 A003425 A052465 * A113015 A024275 A287652
Adjacent sequences: A229579 A229580 A229581 * A229583 A229584 A229585
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Sep 26 2013
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STATUS
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approved
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