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A074536
a(n) = 2^n + 4^n + 9^n.
1
3, 15, 101, 801, 6833, 60105, 535601, 4799481, 43112513, 387683145, 3487834001, 31385255961, 282446317793, 2541932945385, 22877060906801, 205892205869241, 1853024483884673, 16677198879666825, 150094704016738001
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 27 2008: (Start)
G.f.: 1/(1-2*x) + 1/(1-4*x) + 1/(1-9*x).
E.g.f.: exp(2*x) + exp(4*x) + exp(9*x). (End)
MATHEMATICA
Table[2^n + 4^n + 9^n, {n, 0, 20}]
PROG
(Magma) [2^n + 4^n + 9^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved