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A074531
a(n) = 2^n + 3^n + 9^n.
1
3, 14, 94, 764, 6658, 59324, 532234, 4785284, 43053538, 387440684, 3486844474, 31381238804, 282430072018, 2541867430844, 22876797254314, 205891146476324, 1853020231964098, 16677181828937804, 150094635684681754
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 27 2008: (Start)
G.f.: 1/(1-2*x) + 1/(1-3*x) + 1/(1-9*x).
E.g.f.: exp(2*x) + exp(3*x) + exp(9*x). (End)
MATHEMATICA
Table[2^n + 3^n + 9^n, {n, 0, 20}]
LinearRecurrence[{14, -51, 54}, {3, 14, 94}, 20] (* Harvey P. Dale, Nov 29 2019 *)
PROG
(Magma) [2^n + 3^n + 9^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved