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 A258597 a(n) = 13*3^n. 1
 13, 39, 117, 351, 1053, 3159, 9477, 28431, 85293, 255879, 767637, 2302911, 6908733, 20726199, 62178597, 186535791, 559607373, 1678822119, 5036466357, 15109399071, 45328197213, 135984591639, 407953774917, 1223861324751, 3671583974253, 11014751922759 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Also maximum leaf number of the (n+3)-Apollonian network for n >= 0. - Eric W. Weisstein, Jan 17 2018 LINKS Eric Weisstein's World of Mathematics, Apollonian Network Eric Weisstein's World of Mathematics, Maximum Leaf Number Index entries for linear recurrences with constant coefficients, signature (3). FORMULA G.f.: 13/(1-3*x). a(n) = 3*a(n-1). a(n) = 13* A000244(n). MATHEMATICA Table[13 3^n, {n, 0, 30}] 13 3^Range[0, 20] (* Eric W. Weisstein, Jan 17 2018 *) LinearRecurrence[{3}, {13}, 20] (* Eric W. Weisstein, Jan 17 2018 *) CoefficientList[Series[13/(1 - 3 x), {x, 0, 20}], x] (* Eric W. Weisstein, Jan 17 2018 *) PROG (MAGMA) [13*3^n: n in [0..30]]; CROSSREFS Cf. k*3^n: A000244 (k=1,3,9), A008776 (k=2,6), A003946 (k=4), A005030 (k=5), A005032 (k=7), A005051 (k=8), A005052 (k=10), A120354 (k=11), A003946 (k=12), this sequence (k=13), A258598 (k=17), A176413 (k=19). Sequence in context: A283123 A152741 A168235 * A299816 A041324 A220083 Adjacent sequences:  A258594 A258595 A258596 * A258598 A258599 A258600 KEYWORD nonn,easy AUTHOR Vincenzo Librandi, Jun 05 2015 STATUS approved

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Last modified October 23 16:46 EDT 2019. Contains 328373 sequences. (Running on oeis4.)