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 A305155 a(n) = 28*2^n - 15. 3
 13, 41, 97, 209, 433, 881, 1777, 3569, 7153, 14321, 28657, 57329, 114673, 229361, 458737, 917489, 1834993, 3670001, 7340017, 14680049, 29360113, 58720241, 117440497, 234881009, 469762033, 939524081, 1879048177, 3758096369, 7516192753, 15032385521, 30064771057, 60129542129, 120259084273, 240518168561 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS a(n) is the number of edges in the nanostar dendrimer G(n), defined pictorially in the Darafsheh et al. reference (see Fig. 1, where G(2) is shown). REFERENCES M. R. Darafsheh, M. H. Khalifeh, Calculation of the Wiener, Szeged, and PI indices of a certain nanostar dendrimer, Ars Comb., 100, 2011, 289-298. LINKS Muniru A Asiru, Table of n, a(n) for n = 0..700 Index entries for linear recurrences with constant coefficients, signature (3,-2). FORMULA From Colin Barker, May 28 2018: (Start) G.f.: (13 + 2*x) / ((1 - x)*(1 - 2*x)). a(n) = 3*a(n-1) - 2*a(n-2) for n>1. (End) MAPLE seq(28*2^n-15, n = 0..40); MATHEMATICA 28*2^Range[0, 40]-15 (* or *) LinearRecurrence[{3, -2}, {13, 41}, 40] (* Harvey P. Dale, Dec 02 2018 *) PROG (PARI) Vec((13 + 2*x) / ((1 - x)*(1 - 2*x)) + O(x^50)) \\ Colin Barker, May 28 2018 (GAP) List([0..40], n->28*2^n-15); # Muniru A Asiru, May 28 2018 CROSSREFS Cf. A226264, A305156, A305157. Sequence in context: A123972 A167585 A141970 * A355965 A231885 A167240 Adjacent sequences: A305152 A305153 A305154 * A305156 A305157 A305158 KEYWORD nonn,easy AUTHOR Emeric Deutsch, May 28 2018 STATUS approved

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Last modified November 29 08:15 EST 2023. Contains 367429 sequences. (Running on oeis4.)