A074624 a(n) = 8^n + 9^n.
2, 17, 145, 1241, 10657, 91817, 793585, 6880121, 59823937, 521638217, 4560526225, 39970994201, 351149013217, 3091621642217, 27274838966065, 241075504183481, 2134495165562497, 18928981513351817, 168109033806481105
Offset: 0
Links
- G. C. Greubel, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (17,-72).
Programs
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Magma
[8^n+9^n: n in [0..30]]; // G. C. Greubel, Mar 11 2023
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Maple
seq(8^n+9^n,n=0..30); # Robert Israel, Mar 11 2023
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Mathematica
Table[8^n + 9^n, {n, 0, 20}] -
PARI
a(n)=8^n+9^n \\ Charles R Greathouse IV, Apr 08 2016
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SageMath
[8^n+9^n for n in range(31)] # G. C. Greubel, Mar 11 2023
Formula
From Mohammad K. Azarian, Jan 11 2009: (Start)
G.f.: 1/(1-8*x) + 1/(1-9*x).
E.g.f.: exp(8*x) + exp(9*x). (End)
a(n) = 17*a(n-1) - 72*a(n-2) with a(0)=2, a(1)=17. - Vincenzo Librandi, Jul 21 2010