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A184044
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1/9 the number of (n+1) X 6 0..2 arrays with all 2 X 2 subblocks having the same four values.
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2
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81, 87, 97, 117, 153, 225, 361, 633, 1161, 2217, 4297, 8457, 16713, 33225, 66121, 131913, 263241, 525897, 1050697, 2100297, 4198473, 8394825, 16785481, 33566793, 67125321, 134242377, 268468297, 536920137, 1073807433, 2147582025, 4295098441
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
G.f.: x*(81 - 156*x - 164*x^2 + 312*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 3*2^(n/2) + 2^(n+1) + 73 for n even.
a(n) = 2^(n+1) + 2^((n+3)/2) + 73 for n odd.
(End)
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EXAMPLE
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Some solutions for 5 X 6:
..2..0..1..0..2..1....2..1..2..0..2..0....0..2..1..0..1..0....1..2..1..0..1..0
..1..1..2..1..1..0....2..0..2..1..2..1....1..0..0..2..0..2....2..0..2..2..2..2
..2..0..1..0..2..1....2..1..2..0..2..0....0..2..1..0..1..0....1..2..1..0..1..0
..1..1..2..1..1..0....2..0..2..1..2..1....1..0..0..2..0..2....2..0..2..2..2..2
..2..0..1..0..2..1....2..1..2..0..2..0....0..2..1..0..1..0....1..2..1..0..1..0
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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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