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A074556
a(n) = 3^n + 6^n + 8^n.
1
3, 17, 109, 755, 5473, 40787, 309529, 2379275, 18463393, 144315107, 1134267049, 8952908795, 70896790513, 562818102227, 4476415458169, 35654571422315, 284296129664833, 2268726602270147, 18115958853570889, 144724548978127835
OFFSET
0,1
FORMULA
From Mohammad K. Azarian, Dec 30 2008: (Start)
G.f.: 1/(1-3*x) + 1/(1-6*x) + 1/(1-8*x).
E.g.f.: e^(3*x) + e^(6*x) + e^(8*x). (End)
a(n) = 17*a(n-1) - 90*a(n-2) + 144*a(n-3); a(0)=3, a(1)=17, a(2)=109. - Harvey P. Dale, May 19 2011
MATHEMATICA
Table[3^n + 6^n + 8^n, {n, 0, 20}]
LinearRecurrence[{17, -90, 144}, {3, 17, 109}, 21] (* Harvey P. Dale, May 19 2011 *)
PROG
(Magma) [3^n + 6^n + 8^n: n in [0..20]]; // Vincenzo Librandi, May 20 2011
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Aug 23 2002
STATUS
approved