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A074613
a(n) = 4^n + 7^n.
3
2, 11, 65, 407, 2657, 17831, 121745, 839927, 5830337, 40615751, 283523825, 1981521047, 13858064417, 96956119271, 678491508305, 4748635251767, 33237225536897, 232647693856391, 1628482317387185, 11399170063280087
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Jan 11 2009: (Start)
G.f.: 1/(1-4*x) + 1/(1-7*x).
E.g.f.: e^(4*x) + e^(7*x). (End)
a(n) = 11*a(n-1) - 28*a(n-2) with a(0)=2, a(1)=11. - Vincenzo Librandi, Jul 21 2010
MATHEMATICA
Table[4^n + 7^n, {n, 0, 25}]
LinearRecurrence[{11, -28}, {2, 11}, 30] (* Harvey P. Dale, Oct 03 2013 *)
PROG
(Magma) [4^n+7^n: n in [0..30]]; // G. C. Greubel, Mar 10 2023
(SageMath) [4^n+7^n for n in range(31)] # G. C. Greubel, Mar 10 2023
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 26 2002
STATUS
approved