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A183985
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1/4 the number of (n+1) X 9 binary arrays with all 2 X 2 subblock sums the same.
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1
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153, 155, 158, 164, 174, 194, 230, 302, 438, 710, 1238, 2294, 4374, 8534, 16790, 33302, 66198, 131990, 263318, 525974, 1050774, 2100374, 4198550, 8394902, 16785558, 33566870, 67125398, 134242454, 268468374, 536920214, 1073807510, 2147582102
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OFFSET
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1,1
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COMMENTS
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Column 8 of A183986.
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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) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
Conjectures from Colin Barker, Apr 09 2018: (Start)
G.f.: x*(153 - 304*x - 307*x^2 + 608*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 3*2^(n/2-1) + 2^(n-1) + 150 for n even.
a(n) = 2^(n-1) + 2^((n+1)/2) + 150 for n odd.
(End)
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EXAMPLE
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Some solutions for 5 X 9:
..0..0..1..1..1..0..0..1..1....0..1..0..0..1..1..1..1..1
..1..1..0..0..0..1..1..0..0....1..0..1..1..0..0..0..0..0
..0..0..1..1..1..0..0..1..1....0..1..0..0..1..1..1..1..1
..1..1..0..0..0..1..1..0..0....1..0..1..1..0..0..0..0..0
..0..0..1..1..1..0..0..1..1....0..1..0..0..1..1..1..1..1
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CROSSREFS
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Cf. A183986.
Sequence in context: A095226 A346630 A165340 * A184045 A203603 A272767
Adjacent sequences: A183982 A183983 A183984 * A183986 A183987 A183988
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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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