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 A152053 a(n) = A144433(3n+1) + A144433(3n+2) + A144433(3n+3). 0
 27, 36, 81, 72, 135, 108, 189, 144, 243, 180, 297, 216, 351, 252, 405, 288, 459, 324, 513, 360, 567, 396, 621, 432, 675, 468, 729, 504, 783, 540, 837, 576, 891, 612, 945, 648, 999, 684, 1053, 720, 1107 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS All terms are multiples of 9. LINKS Index entries for linear recurrences with constant coefficients, signature (0, 2, 0, -1). FORMULA From R. J. Mathar, May 21 2009: (Start) G.f.: 9*(3+4*x+3*x^2)/((x-1)^2*(1+x)^2). a(n) = 45*(n+1)/2 + 9*(-1)^n*(n+1)/2. (End) a(n) = 9*A106833(n+1). - Jean-François Alcover, Feb 02 2019, after Paul Curtz a(n+4) = 2*a(n+2) - a(n). - Jianing Song, Feb 04 2019 MATHEMATICA Table[(9/2)(5 + (-1)^n)(n + 1), {n, 0, 40}] (* Jean-François Alcover, Feb 02 2019 *) LinearRecurrence[{0, 2, 0, -1}, {27, 36, 81, 72}, 50] (* Harvey P. Dale, Nov 07 2019 *) PROG (PARI) a(n) = 45*(n+1)/2 + 9*(-1)^n*(n+1)/2 \\ Jianing Song, Feb 04 2019 CROSSREFS Cf. A106933, A144433. Sequence in context: A326893 A160119 A160379 * A166649 A025145 A266963 Adjacent sequences:  A152050 A152051 A152052 * A152054 A152055 A152056 KEYWORD nonn,easy AUTHOR Paul Curtz, Nov 22 2008 EXTENSIONS Edited by R. J. Mathar, May 21 2009 STATUS approved

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Last modified June 17 22:14 EDT 2021. Contains 345086 sequences. (Running on oeis4.)