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A173770
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a(n)=(4*10^n-13)/9.
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3
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3, 43, 443, 4443, 44443, 444443, 4444443, 44444443, 444444443, 4444444443, 44444444443, 444444444443, 4444444444443, 44444444444443, 444444444444443, 4444444444444443, 44444444444444443, 444444444444444443
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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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a(n)=10*a(n-1)+13 (with a(1)=3).
G.f. x*(3+10*x) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Aug 23 2011
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EXAMPLE
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For n=2, a(2)=10*3+13=43; n=3, a(3)=10*43+13=443; n=4, a(4)=10*443+13=4443
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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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