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A210101
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Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having one or three distinct values, and new values 0..2 introduced in row major order.
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1
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30, 225, 1690, 12725, 95830, 721705, 5435250, 40933565, 308275950, 2321665905, 17484765130, 131680019525, 991699197190, 7468614458425, 56247097997730, 423604143817805, 3190217398715550, 24025938366280065, 180942438158822650
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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) = 8*a(n-1) - 3*a(n-2) - 4*a(n-3).
G.f.: 5*x*(6 - 3*x - 4*x^2) / ((1 - x)*(1 - 7*x - 4*x^2)).
a(n) = (1/13)*2^(-2-n)*(13*2^(1+n) + (117-11*sqrt(65))*(7-sqrt(65))^n + (7+sqrt(65))^n*(117+11*sqrt(65))).
(End)
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EXAMPLE
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Some solutions for n=4:
0 0 0 0 0 0 0 1 1 0 1 0 0 0 1 0 1 2 0 1 2
0 0 0 0 0 0 1 2 0 2 1 2 0 0 2 0 2 0 1 2 0
1 2 1 0 0 0 1 0 1 2 0 1 2 1 1 2 1 2 1 0 1
1 0 2 0 0 0 0 2 0 0 1 2 2 0 2 1 0 1 0 2 2
0 2 1 0 0 0 2 1 2 0 2 0 2 1 0 0 2 2 2 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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