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A173193
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a(n) = (2*10^n+43)/9.
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1
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7, 27, 227, 2227, 22227, 222227, 2222227, 22222227, 222222227, 2222222227, 22222222227, 222222222227, 2222222222227, 22222222222227, 222222222222227, 2222222222222227, 22222222222222227, 222222222222222227
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OFFSET
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1,1
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COMMENTS
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n-1 2's followed by a 7.
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LINKS
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FORMULA
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a(n) = a(n-1)+2*10^(n-1) with n>1, a(1)=7. - Zak Seidov, Dec 05 2010
a(n) = 11*a(n-1)-10*a(n-2).
G.f.: -x*(50*x-7)/((x-1)*(10*x-1)). (End)
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MATHEMATICA
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Table[FromDigits[PadLeft[{7}, n, 2]], {n, 20}] (* or *) LinearRecurrence[{11, -10}, {7, 27}, 20] (* Harvey P. Dale, Jan 06 2023 *)
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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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EXTENSIONS
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STATUS
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approved
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