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A074621 a(n) = 6^n + 9^n. 1
2, 15, 117, 945, 7857, 66825, 578097, 5062905, 44726337, 397498185, 3547250577, 31743856665, 284606318817, 2554926522345, 22955156619057, 206361317079225, 1855841298759297, 16694108359111305, 150196195253667537 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (15,-54).

FORMULA

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

G.f.: 1/(1-6*x) + 1/(1-9*x).

E.g.f.: e^(6*x) + e^(9*x). (End)

a(n) = 15*a(n-1) - 54*a(n-2) with a(0)=2, a(1)=15. - Vincenzo Librandi, Jul 21 2010

MATHEMATICA

Table[6^n + 9^n, {n, 0, 20}]

CROSSREFS

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

Sequence in context: A052861 A300910 A161937 * A185758 A052448 A168502

Adjacent sequences:  A074618 A074619 A074620 * A074622 A074623 A074624

KEYWORD

easy,nonn

AUTHOR

Robert G. Wilson v, Aug 26 2002

STATUS

approved

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Last modified May 27 02:54 EDT 2019. Contains 323597 sequences. (Running on oeis4.)