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A074575
a(n) = 5^n + 7^n + 9^n.
1
3, 21, 155, 1197, 9587, 78981, 664715, 5684637, 49202147, 429727221, 3779025275, 33407214477, 296514964307, 2639975541861, 23561119043435, 210669211182717, 1886405707312067, 16910575153106901, 151726863592175195
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 26 2008: (Start)
G.f.: 1/(1-5*x) + 1/(1-7*x) + 1/(1-9*x).
E.g.f.: e^(5*x) + e^(7*x) + e^(9*x). (End)
MATHEMATICA
Table[5^n + 7^n + 9^n, {n, 0, 20}]
LinearRecurrence[{21, -143, 315}, {3, 21, 155}, 20] (* Harvey P. Dale, Jul 14 2019 *)
PROG
(Magma) [5^n + 7^n + 9^n: n in [0..20]]; // Vincenzo Librandi, May 20 2011
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved