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A074549
a(n) = 3^n + 4^n + 7^n.
1
3, 14, 74, 434, 2738, 18074, 122474, 842114, 5836898, 40635434, 283582874, 1981698194, 13858595858, 96957713594, 678496291274, 4748649600674, 33237268583618, 232647822996554, 1628482704807674, 11399171225541554
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 28 2008: (Start)
G.f.: 1/(1-3*x) + 1/(1-4*x) + 1/(1-7*x).
E.g.f.: exp(3*x) + exp(4*x) + exp(7*x). (End)
a(n) = 14*a(n-1) - 61*a(n-2) + 84*a(n-3).
MATHEMATICA
Table[3^n + 4^n + 7^n, {n, 0, 20}]
LinearRecurrence[{14, -61, 84}, {3, 14, 74}, 20] (* Harvey P. Dale, Jun 11 2024 *)
PROG
(Magma) [3^n + 4^n + 7^n: n in [0..30]]; // Vincenzo Librandi, Jun 13 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved