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A196012
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Number of n X 3 0..4 arrays with each element equal to the number its horizontal and vertical neighbors within one of itself.
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1
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1, 1, 2, 7, 13, 16, 32, 65, 125, 211, 390, 732, 1368, 2478, 4555, 8417, 15564, 28583, 52598, 96921, 178684, 328956, 605723, 1115678, 2055336, 3785356, 6971537, 12840292, 23650713, 43560381, 80229677, 147768685, 272167135, 501285666
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OFFSET
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1,3
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COMMENTS
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Column 3 of A196017.
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..200
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FORMULA
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Empirical: a(n) = a(n-1) +a(n-2) +3*a(n-4) -a(n-5) -2*a(n-6).
Empirical g.f.: x*(1 - x)*(1 + x + x^2 + 5*x^3 + 6*x^4) / (1 - x - x^2 - 3*x^4 + x^5 + 2*x^6). - Colin Barker, May 08 2018
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EXAMPLE
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All solutions for n=4:
..2..2..0....2..2..2....0..2..2....2..3..2....2..2..2....2..3..2....2..2..2
..3..3..2....2..0..2....2..3..3....3..4..3....2..0..2....3..3..3....2..0..2
..2..0..2....3..3..3....2..0..2....3..4..3....2..3..3....2..0..2....3..3..2
..2..2..2....2..3..2....2..2..2....2..3..2....0..2..2....2..2..2....2..2..0
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CROSSREFS
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Cf. A196017.
Sequence in context: A063222 A030592 A154313 * A065104 A138645 A191060
Adjacent sequences: A196009 A196010 A196011 * A196013 A196014 A196015
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Sep 26 2011
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STATUS
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approved
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