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 A083813 a(n) = 3*(10^n-1). 3
 27, 297, 2997, 29997, 299997, 2999997, 29999997, 299999997, 2999999997, 29999999997, 299999999997, 2999999999997, 29999999999997, 299999999999997 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 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 LINKS Table of n, a(n) for n=1..14. MATHEMATICA 3(10^Range[20]-1) (* or *) Table[10 FromDigits[PadRight[{2}, n, 9]]+7, {n, 20}] (* Harvey P. Dale, Jan 25 2020 *) CROSSREFS Essentially a duplicate of A086574. Cf. A000042, A083811, A083812. Sequence in context: A115246 A202126 A022687 * A086574 A274832 A125415 Adjacent sequences: A083810 A083811 A083812 * A083814 A083815 A083816 KEYWORD nonn AUTHOR Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 08 2003 EXTENSIONS Edited by M. F. Hasler, Jul 29 2016 STATUS approved

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Last modified May 30 19:43 EDT 2023. Contains 363059 sequences. (Running on oeis4.)