login
A074534
a(n) = 2^n + 4^n + 7^n.
1
3, 13, 69, 415, 2673, 17863, 121809, 840055, 5830593, 40616263, 283524849, 1981523095, 13858068513, 96956127463, 678491524689, 4748635284535, 33237225602433, 232647693987463, 1628482317649329, 11399170063804375
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 27 2008: (Start)
G.f.: 1/(1-2*x) + 1/(1-4*x) + 1/(1-7*x).
E.g.f.: exp(2*x) + exp(4*x) + exp(7*x). (End)
MATHEMATICA
Table[2^n + 4^n + 7^n, {n, 0, 20}]
PROG
(Magma) [2^n + 4^n + 7^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved