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A074607 a(n) = 3^n + 6^n. 2
2, 9, 45, 243, 1377, 8019, 47385, 282123, 1686177, 10097379, 60525225, 362974203, 2177313777, 13062288339, 78368947065, 470199333483, 2821152954177, 16926788584899, 101560344088905, 609360902271963, 3656161926847377 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (9,-18).

FORMULA

From Mohammad K. Azarian, Jan 11 2009: (Start)

G.f.: 1/(1-3*x) + 1/(1-6*x).

E.g.f.: e^(3*x) + e^(6*x). (End)

a(n) = 9*a(n-1) - 18*a(n-2) with a(0)=2, a(1)=9. - Vincenzo Librandi, Jul 21 2010

G.f.: G(0), where G(k)= 1 + 2^k/(1 - 3*x/(3*x + 2^k/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jul 22 2013

MATHEMATICA

Table[3^n + 6^n, {n, 0, 25}]

PROG

(MAGMA) [3^n + 6^n: n in [0..35]]; // Vincenzo Librandi, Apr 30 2011

CROSSREFS

Cf. A000051, A034472, A052539, A034474, A062394, A034491, A062395, A062396, A007689, A063376, A063481, A074600..A074624.

Sequence in context: A264122 A233505 A228767 * A251178 A162725 A268171

Adjacent sequences:  A074604 A074605 A074606 * A074608 A074609 A074610

KEYWORD

easy,nonn

AUTHOR

Robert G. Wilson v, Aug 25 2002

STATUS

approved

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Last modified March 25 01:17 EDT 2019. Contains 321450 sequences. (Running on oeis4.)