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A267468
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Number of length-n 0..5 arrays with no following elements larger than the first repeated value.
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1
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6, 36, 201, 1096, 5921, 31880, 171601, 925176, 5002641, 27155800, 148092161, 811801256, 4475004961, 24813260520, 138416411121, 776822970136, 4385905536881, 24907563562040, 142244725848481, 816667390335816
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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) = 26*a(n-1) -280*a(n-2) +1610*a(n-3) -5299*a(n-4) +9884*a(n-5) -9540*a(n-6) +3600*a(n-7).
G.f.: x*(6 - 120*x + 945*x^2 - 3710*x^3 + 7539*x^4 - 7336*x^5 + 2556*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)^2*(1 - 6*x)).
a(n) = (-75 - 25*2^(1+n) - 50*3^n + 25*2^(1+n)*3^n - 75*4^n + 413*5^n + 12*5^n*n) / 300.
(End)
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EXAMPLE
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Some solutions for n=7:
..2....1....0....4....3....5....2....0....3....3....4....4....0....4....1....3
..0....3....3....1....1....0....0....4....0....3....3....3....3....4....4....1
..4....2....4....2....2....1....4....1....3....1....0....5....1....0....5....2
..0....4....1....3....0....5....0....5....0....0....3....1....2....0....2....1
..3....0....5....2....4....4....2....0....3....0....2....0....5....3....0....4
..4....2....3....2....4....1....5....4....2....3....0....1....5....2....4....3
..0....4....0....1....0....3....2....3....1....2....3....0....4....1....4....5
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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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