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A155658
a(n) = 11^n + 7^n - 1.
17
1, 17, 169, 1673, 17041, 177857, 1889209, 20310713, 220123681, 2398301297, 26219899849, 287288997353, 3152269663921, 34619601154337, 380428056656089, 4181995730925593, 45982962794141761, 505679659013280977
OFFSET
0,2
FORMULA
G.f.: 1/(1-11*x) + 1/(1-7*x) - 1/(1-x).
E.g.f.: exp(11*x) + exp(7*x) - exp(x).
a(n) = 18*a(n-1)-77*a(n-2)-60 with a(0)=1, a(1)=17. - Vincenzo Librandi, Jul 21 2010
MATHEMATICA
Table[11^n+7^n-1, {n, 0, 20}] (* G. C. Greubel, Nov 18 2018 *)
PROG
(PARI) a(n)=11^n+7^n-1 \\ Charles R Greathouse IV, Jun 11 2015
(Magma) [11^n+7^n-1: n in [0..20]]; // G. C. Greubel, Nov 18 2018
(Sage) [11^n+7^n-1 for n in range(20)] # G. C. Greubel, Nov 18 2018
(GAP) List([0..20], n -> 11^n+7^n-1); # G. C. Greubel, Nov 18 2018
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Jan 31 2009
STATUS
approved