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A228462
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Number of arrays of maxima of three adjacent elements of some length 7 0..n array.
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1
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17, 91, 310, 821, 1847, 3703, 6812, 11721, 19117, 29843, 44914, 65533, 93107, 129263, 175864, 235025, 309129, 400843, 513134, 649285, 812911, 1007975, 1238804, 1510105, 1826981, 2194947, 2619946, 3108365, 3667051, 4303327, 5025008, 5840417
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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) = (2/15)*n^5 + (7/6)*n^4 + (25/6)*n^3 + (19/3)*n^2 + (21/5)*n + 1.
G.f.: x*(17 - 11*x + 19*x^2 - 14*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=4:
..2....2....0....2....3....4....4....3....3....4....4....4....4....2....4....1
..0....1....0....1....3....4....4....1....1....2....2....3....2....1....0....4
..2....1....1....0....2....3....3....2....1....0....2....1....1....2....1....4
..3....0....3....2....2....2....2....2....1....2....1....3....2....2....1....4
..3....0....3....4....1....2....1....4....0....3....2....4....4....2....2....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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