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 A015581 a(n) = 9*a(n-1) + 5*a(n-2). 3
 0, 1, 9, 86, 819, 7801, 74304, 707741, 6741189, 64209406, 611590599, 5825362421, 55486214784, 528502745161, 5033955780369, 47948115749126, 456702820643979, 4350065964541441, 41434107784092864, 394657299879542981, 3759086237836351149, 35805062639924875246 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS A linear 2nd-order recurrence. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (9,5). FORMULA G.f.: x/(1 - 9*x - 5*x^2). - R. J. Mathar, Dec 02 2007 a(n) = (1/101)*sqrt(101)*(((9/2) + (1/2)*sqrt(101))^n - ((9/2) - (1/2)*sqrt(101))^n). - Paolo P. Lava, Jan 13 2009 MATHEMATICA Join[{a=0, b=1}, Table[c=9*b+5*a; a=b; b=c, {n, 60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 27 2011 *) LinearRecurrence[{9, 5}, {0, 1}, 30] (* Vincenzo Librandi, Nov 15 2012 *) PROG (Sage) [lucas_number1(n, 9, -5) for n in range(0, 19)] # Zerinvary Lajos, Apr 26 2009 (MAGMA) [n le 2 select n-1 else 9*Self(n-1) + 5*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 15 2012 (PARI) x='x+O('x^30); concat([0], Vec(x/(1-9*x-5*x^2))) \\ G. C. Greubel, Jan 06 2018 CROSSREFS Cf. A015579, A099371. Sequence in context: A029711 A204465 A276242 * A152261 A028339 A180751 Adjacent sequences:  A015578 A015579 A015580 * A015582 A015583 A015584 KEYWORD nonn,easy AUTHOR EXTENSIONS Extended by T. D. Noe, May 23 2011 STATUS approved

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Last modified April 6 12:19 EDT 2020. Contains 333273 sequences. (Running on oeis4.)