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A095752
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a(n) = (1/9)*(-1+10^n)*(4*n+3)
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0
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7, 121, 1665, 21109, 255553, 2999997, 34444441, 388888885, 4333333329, 47777777773, 522222222217, 5666666666661, 61111111111105, 655555555555549, 6999999999999993, 74444444444444437, 788888888888888881
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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Numbers with increasingly larger and larger one-digit centers.
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REFERENCES
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Discovered by Jason Earls.
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LINKS
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FORMULA
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O.g.f.: -x*(2*x+7)*(5*x-1)/[(-1+x)^2*(-1+10*x)^2]. - R. J. Mathar, Feb 26 2008
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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