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A083813
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a(n) = 3*(10^n-1).
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3
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27, 297, 2997, 29997, 299997, 2999997, 29999997, 299999997, 2999999997, 29999999997, 299999999997, 2999999999997, 29999999999997, 299999999999997
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OFFSET
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1,1
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COMMENTS
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Original definition: 3n+1 is the digit reversal of n+1.
1. a(n) = 27 + 270 + 2700 + ... up to n terms = sum of n terms of the geometric progression with the first term 27 and common ratio 10.
2. a(n) = 27*A000042(n) (the unary sequence).
Equals A086574 restricted to positive indices. See that entry for many more comments, formulas and references. - M. F. Hasler, Jul 29 2016
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LINKS
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MATHEMATICA
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3(10^Range[20]-1) (* or *) Table[10 FromDigits[PadRight[{2}, n, 9]]+7, {n, 20}] (* Harvey P. Dale, Jan 25 2020 *)
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CROSSREFS
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Essentially a duplicate of A086574.
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 08 2003
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EXTENSIONS
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STATUS
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approved
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