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A236942
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Number of (n+1) X (1+1) 0..3 arrays with the maximum of every 2 X 2 subblock equal.
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1
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256, 2796, 30698, 357316, 4195956, 50119046, 601976968, 7271574636, 88068458546, 1068829320076, 12986262880788, 157905941911406, 1920929508184336, 23375169249987756, 284496769631574458, 3462985011143368276
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 16*a(n-1) - 650*a(n-3) + 596*a(n-4) + 5184*a(n-5) - 1365*a(n-6) - 3780*a(n-7).
Empirical g.f.: 2*x*(128 - 650*x - 7019*x^2 + 16274*x^3 + 71862*x^4 - 28035*x^5 - 56700*x^6) / ((1 - x)*(1 - 3*x - 3*x^2)*(1 - 5*x - 20*x^2)*(1 - 7*x - 63*x^2)). - Colin Barker, Oct 21 2018
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EXAMPLE
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Some solutions for n=3:
..1..3....0..3....3..1....3..0....0..1....1..2....3..0....0..3....0..0....2..3
..3..2....0..2....0..2....0..2....0..3....0..2....0..2....1..3....3..1....2..2
..3..2....3..0....3..3....3..2....2..3....1..0....0..3....1..3....2..0....3..3
..2..3....0..3....1..3....3..2....2..0....0..2....0..0....2..2....3..0....3..1
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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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