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A183630
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Number of (n+1) X 8 0..2 arrays with every 2 X 2 subblock summing to 4.
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1
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7075, 8109, 10195, 14421, 23035, 40749, 77635, 155781, 325195, 703389, 1577875, 3681141, 8950555, 22678029, 59698915, 162438501, 454011115, 1295436669, 3753128755, 10993035861, 32446418875, 96273891309, 286690955395
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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) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3).
G.f.: x*(7075 - 34341*x + 39366*x^2) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).
a(n) = 6050 + 127*2^(2+n) + 3^(1+n).
(End)
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EXAMPLE
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Some solutions for 3 X 8:
0 0 1 2 1 1 2 1 1 2 1 1 1 1 2 0 0 2 0 2 0 0 0 2
2 2 1 0 1 1 0 1 1 0 1 1 1 1 0 2 2 0 2 0 2 2 2 0
0 0 1 2 1 1 2 1 1 2 1 1 1 1 2 0 0 2 0 2 0 0 0 2
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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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