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A074554
a(n) = 3^n + 5^n + 9^n.
1
3, 17, 115, 881, 7267, 62417, 547795, 4863281, 43443907, 389393297, 3496609075, 31430064881, 282674208547, 2543088125777, 22882900753555, 205921664021681, 1853172819789187, 16677944768259857, 150098450381685235
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 30 2008: (Start)
G.f.: 1/(1-3*x) + 1/(1-5*x) + 1/(1-9*x).
E.g.f.: exp(3*x) + exp(5*x) + exp(9*x). (End)
a(n) = 17*a(n-1) - 87*a(n-2) + 135*a(n-3).
MATHEMATICA
Table[3^n + 5^n + 9^n, {n, 0, 20}]
LinearRecurrence[{17, -87, 135}, {3, 17, 115}, 30] (* Harvey P. Dale, Nov 27 2012 *)
PROG
(Magma) [3^n + 5^n + 9^n: n in [0..30]]; // Vincenzo Librandi, Jun 13 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved