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A184047
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1/9 the number of (n+1) X 9 0..2 arrays with all 2 X 2 subblocks having the same four values.
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1
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561, 567, 577, 597, 633, 705, 841, 1113, 1641, 2697, 4777, 8937, 17193, 33705, 66601, 132393, 263721, 526377, 1051177, 2100777, 4198953, 8395305, 16785961, 33567273, 67125801, 134242857, 268468777, 536920617, 1073807913, 2147582505, 4295098921
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OFFSET
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1,1
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COMMENTS
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Column 8 of A184048.
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..158
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FORMULA
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Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
Conjectures from Colin Barker, Apr 10 2018: (Start)
G.f.: x*(561 - 1116*x - 1124*x^2 + 2232*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 3*2^(n/2) + 2^(n+1) + 553 for n even.
a(n) = 2^(n+1) + 2^((n+3)/2) + 553 for n odd.
(End)
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EXAMPLE
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Some solutions for 5 X 9:
..2..0..2..0..0..1..0..1..2....1..1..0..0..0..0..1..0..1
..0..1..0..1..2..0..2..0..0....0..0..1..1..1..1..0..1..0
..2..0..2..0..0..1..0..1..2....1..1..0..0..0..0..1..0..1
..0..1..0..1..2..0..2..0..0....0..0..1..1..1..1..0..1..0
..2..0..2..0..0..1..0..1..2....1..1..0..0..0..0..1..0..1
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CROSSREFS
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Cf. A184048.
Sequence in context: A274443 A247906 A278338 * A344673 A344706 A259172
Adjacent sequences: A184044 A184045 A184046 * A184048 A184049 A184050
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin, Jan 08 2011
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STATUS
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approved
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