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A074611 4^n + 5^n. 3
2, 9, 41, 189, 881, 4149, 19721, 94509, 456161, 2215269, 10814201, 53022429, 260917841, 1287811989, 6371951081, 31591319949, 156882857921, 780119322309, 3883416742361, 19348364235069, 96466943268401, 481235204714229 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (9,-20).

FORMULA

G.f.: 1/(1-4*x)+1/(1-5*x). E.g.f.: e^(4*x)+e^(5*x). [Mohammad K. Azarian, Jan 11 2009]

a(n) = 9*a(n-1) - 20*a(n-2) with n>1, a(0)=2, a(1)=9. [Vincenzo Librandi, Jul 21 2010]

MATHEMATICA

Table[4^n + 5^n, {n, 0, 25}]

CoefficientList[Series[1/(1 - 4 x) + 1/(1 - 5 x), {x, 0, 30}], x] (* Vincenzo Librandi, Feb 06 2013 *)

PROG

(MAGMA) [4^n + 5^n: n in [0..30]]; // Vincenzo Librandi, Feb 06 2013

CROSSREFS

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

Sequence in context: A217190 A020698 A128752 * A292078 A270766 A181375

Adjacent sequences:  A074608 A074609 A074610 * A074612 A074613 A074614

KEYWORD

easy,nonn

AUTHOR

Robert G. Wilson v, Aug 25 2002

STATUS

approved

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Last modified October 15 20:04 EDT 2019. Contains 328037 sequences. (Running on oeis4.)