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 A328604 G.f.: (1 + 7*x) / (1 - 2*x - 9*x^2). 3
 1, 9, 27, 135, 513, 2241, 9099, 38367, 158625, 662553, 2752731, 11468439, 47711457, 198638865, 826680843, 3441111471, 14322350529, 59614704297, 248130563355, 1032793465383, 4298762000961, 17892665190369, 74474188389387, 309982363492095, 1290232422488673, 5370306116406201 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Colin Barker, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (2,9). FORMULA a(n) = 2*a(n-1) + 9*a(n-2) for n>1. - Colin Barker, Oct 21 2019 a(n)/a(n-1) ~ 1 + sqrt(10). PROG (PARI) Vec((1 + 7*x) / (1 - 2*x - 9*x^2) + O(x^30)) \\ Colin Barker, Dec 13 2019 CROSSREFS Sequence in context: A053762 A126322 A020279 * A230185 A217640 A227474 Adjacent sequences:  A328601 A328602 A328603 * A328605 A328606 A328607 KEYWORD nonn,easy AUTHOR Kyle MacLean Smith, Oct 20 2019 EXTENSIONS Edited by N. J. A. Sloane, Dec 05 2019 STATUS approved

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Last modified January 23 13:47 EST 2020. Contains 331171 sequences. (Running on oeis4.)