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 A020729 Pisot sequences E(2,10), L(2,10), P(2,10), T(2,10). 6
 2, 10, 50, 250, 1250, 6250, 31250, 156250, 781250, 3906250, 19531250, 97656250, 488281250, 2441406250, 12207031250, 61035156250, 305175781250, 1525878906250, 7629394531250, 38146972656250, 190734863281250, 953674316406250, 4768371582031250, 23841857910156250 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 Shalosh B. Ekhad, N. J. A. Sloane and Doron Zeilberger, Automated Proof (or Disproof) of Linear Recurrences Satisfied by Pisot Sequences, arXiv preprint, arXiv:1609.05570 [math.NT], 2016. Tanya Khovanova, Recursive Sequences. Index entries for linear recurrences with constant coefficients, signature (5). FORMULA a(n) = 2*5^n. a(n) = 5*a(n-1). G.f.: 2/(1-5*x). - Philippe Deléham, Nov 23 2008 From Amiram Eldar, May 08 2023: (Start) Sum_{n>=0} 1/a(n) = 5/8. Sum_{n>=0} (-1)^n/a(n) = 5/12. Product_{n>=0} (1 - 1/a(n)) = A132021. (End) MATHEMATICA Join[{a=2}, Table[a=5*a, {n, 0, 60}]] (* Vladimir Joseph Stephan Orlovsky, Jun 09 2011 *) Join[{2}, NestList[5#&, 10, 30]] (* Harvey P. Dale, Jan 19 2013 *) PROG (Magma) [2*5^n: n in [0..25]]; // Vincenzo Librandi, Sep 15 2011 CROSSREFS Essentially a duplicate of A020699. See A008776 for definitions of Pisot sequences. Cf. A132021. Sequence in context: A015954 A015949 A020699 * A110170 A026332 A027908 Adjacent sequences: A020726 A020727 A020728 * A020730 A020731 A020732 KEYWORD nonn,easy AUTHOR David W. Wilson STATUS approved

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Last modified September 10 21:37 EDT 2024. Contains 375795 sequences. (Running on oeis4.)