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3^n + 6^n + 9^n.
1

%I #12 Sep 08 2022 08:45:07

%S 3,18,126,972,7938,67068,578826,5065092,44732898,397517868,3547309626,

%T 31744033812,284606850258,2554928116668,22955161402026,

%U 206361331428132,1855841341806018,16694108488251468,150196195641088026

%N 3^n + 6^n + 9^n.

%H Vincenzo Librandi, <a href="/A074557/b074557.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (18,-99,162).

%F G.f.: 1/(1-3*x)+1/(1-6*x)+1/(1-9*x). E.g.f.: exp(3*x)+exp(6*x)+exp(9*x). [From _Mohammad K. Azarian_, Dec 30 2008]

%t Table[3^n + 6^n + 9^n, {n, 0, 20}]

%o (Magma) [3^n + 6^n + 9^n: n in [0..20]]; // Vincenzo Librandi, Aug 24 2011

%Y Cf. A001550, A001576, A034513, A001579, A074501 - A074580.

%K easy,nonn

%O 0,1

%A _Robert G. Wilson v_, Aug 23 2002