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A229281
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Number of ascending runs in {1,...,7}^n.
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2
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0, 7, 77, 735, 6517, 55223, 453789, 3647119, 28824005, 224827239, 1735205101, 13276336703, 100843663893, 761270796055, 5716451614013, 42728053589487, 318086621166181, 2359538070441671, 17447288549040525, 128644674234925471, 946108300385970869
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: -7*(3*x-1)*x/(7*x-1)^2.
a(n) = 7^(n-1)*(4*n+3) for n>0, a(0) = 0.
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MAPLE
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a:= n-> `if`(n=0, 0, 7^(n-1)*(4*n+3)):
seq(a(n), n=0..30);
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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