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A249711
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Number of length 5+3 0..n arrays with every four consecutive terms having the maximum of some two terms equal to the minimum of the remaining two terms.
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1
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38, 377, 1724, 5425, 13666, 29673, 57912, 104289, 176350, 283481, 437108, 650897, 940954, 1326025, 1827696, 2470593, 3282582, 4294969, 5542700, 7064561, 8903378, 11106217, 13724584, 16814625, 20437326, 24658713, 29550052, 35188049, 41655050
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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) = (5/3)*n^5 + 10*n^4 + 16*n^3 + 8*n^2 + (4/3)*n + 1.
G.f.: x*(38 + 149*x + 32*x^2 - 24*x^3 + 6*x^4 - x^5) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)
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EXAMPLE
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Some solutions for n=6:
..0....2....1....1....0....2....5....4....0....5....2....3....0....6....3....4
..1....2....5....5....4....5....2....4....3....2....2....3....2....0....3....2
..5....0....6....6....3....3....3....6....5....6....2....3....2....2....3....1
..1....6....5....5....3....3....3....4....3....5....6....6....4....2....1....2
..0....2....5....5....3....3....5....4....1....5....1....1....2....2....3....2
..1....2....5....5....0....0....3....0....3....5....2....3....2....2....5....2
..6....2....4....4....6....3....2....4....3....3....2....3....1....1....3....3
..1....2....5....6....3....5....3....5....5....5....3....6....6....5....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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