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A074570
a(n) = 4^n + 8^n + 9^n.
1
3, 21, 161, 1305, 10913, 92841, 797681, 6896505, 59889473, 521900361, 4561574801, 39975188505, 351165790433, 3091688751081, 27275107401521, 241076577925305, 2134499460529793, 18928998693221001, 168109102525957841
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 30 2008: (Start)
G.f.: 1/(1-4*x) + 1/(1-8*x) + 1/(1-9*x).
E.g.f.: exp(4*x) + exp(8*x) + exp(9*x). (End)
MATHEMATICA
Table[4^n + 8^n + 9^n, {n, 0, 20}]
PROG
(Magma) [4^n + 8^n + 9^n: n in [0..20]]; // Vincenzo Librandi, Aug 14 2011
(PARI) vector(20, n, n--; 4^n + 8^n + 9^n) \\ G. C. Greubel, Nov 08 2018
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved