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 A138233 a(n) = 2^(2*n+1) + 3^(2*n+1). 2
 5, 35, 275, 2315, 20195, 179195, 1602515, 14381675, 129271235, 1162785755, 10462450355, 94151567435, 847322163875, 7625731702715, 68630914235795, 617675543767595, 5559069156490115, 50031579458738075, 450284043329950835 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Subsequence of A008587. LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (13,-36). FORMULA a(n) = 5*A096951(n). a(n+1) = 4*a(n) + 5*3^(2*n+1), a(0) = 5. O.g.f.: 5*x*(7-36*x)/((1-4*x)*(1-9*x)). - R. J. Mathar, Apr 24 2008 E.g.f.: 2*exp(4*x) + 3*exp(9*x). - G. C. Greubel, Mar 11 2023 MATHEMATICA LinearRecurrence[{13, -36}, {5, 35}, 19] (* Ray Chandler, Jul 14 2017 *) 2^#+3^#&/@(2*Range[0, 20]+1) (* Harvey P. Dale, Sep 25 2019 *) PROG (Magma) [2^(2*n+1) + 3^(2*n+1): n in [0..30]]; // G. C. Greubel, Mar 11 2023 (SageMath) [2^(2*n+1) + 3^(2*n+1) for n in range(31)] # G. C. Greubel, Mar 11 2023 CROSSREFS Cf. A008587, A096951, A138199. Sequence in context: A087630 A084135 A229111 * A322666 A248053 A369157 Adjacent sequences: A138230 A138231 A138232 * A138234 A138235 A138236 KEYWORD nonn AUTHOR Reinhard Zumkeller, Mar 07 2008 STATUS approved

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Last modified February 22 02:07 EST 2024. Contains 370239 sequences. (Running on oeis4.)