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A210136
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Number of (n+1) X 2 0..3 arrays containing all values 0..3 with every 2 X 2 subblock having one, two or four distinct values, and new values 0..3 introduced in row major order.
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1
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1, 10, 105, 1018, 9157, 77934, 638065, 5084818, 39762621, 306822358, 2345284009, 17806600698, 134548145461, 1013159874046, 7610346917985, 57063648570850, 427326717363757, 3197140079770278, 23904313586774425, 178642318573382986
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 18*a(n-1) - 111*a(n-2) + 266*a(n-3) - 180*a(n-4) - 24*a(n-5) + 32*a(n-6).
Empirical g.f.: x*(1 - 8*x + 36*x^2 - 28*x^3 + 8*x^4) / ((1 - x)*(1 - 4*x)*(1 - 5*x - 2*x^2)*(1 - 8*x + 4*x^2)). - Colin Barker, Jul 14 2018
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EXAMPLE
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Some solutions for n=4:
0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 1 0 0
1 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0
0 0 2 3 0 1 1 1 0 0 1 0 0 0 0 1 2 3 1 1
2 2 0 1 0 1 0 1 0 1 1 0 1 0 2 3 3 2 0 1
2 3 3 2 2 3 2 3 2 3 2 3 2 3 2 3 0 1 2 3
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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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