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A075858
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n followed by n 1's.
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2
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11, 211, 3111, 41111, 511111, 6111111, 71111111, 811111111, 9111111111, 101111111111, 1111111111111, 12111111111111, 131111111111111, 1411111111111111, 15111111111111111, 161111111111111111, 1711111111111111111, 18111111111111111111, 191111111111111111111
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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REFERENCES
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J. Earls, On Smarandache Repunit N Numbers, Smarandache Notions Journal (2004), Vol. 14.1, pp 251-258.
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LINKS
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FORMULA
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a(n) = n*10^n+(10^n-1)/9.
G.f.: x*(11-20*x)/((1-x)*(1-20*x+100*x^2)). a(n)=20*a(n-1)-100*a(n-2)-9, n>1. - Michael Somos, Oct 29, 2002
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MAPLE
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MATHEMATICA
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PROG
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(PARI) a(n)=if(n<1, 0, n*10^n+(10^n-1)/9)
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CROSSREFS
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KEYWORD
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easy,nonn,less
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AUTHOR
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STATUS
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approved
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