A074531 a(n) = 2^n + 3^n + 9^n.

3, 14, 94, 764, 6658, 59324, 532234, 4785284, 43053538, 387440684, 3486844474, 31381238804, 282430072018, 2541867430844, 22876797254314, 205891146476324, 1853020231964098, 16677181828937804, 150094635684681754

Offset: 0

Author

Robert G. Wilson v, Aug 23 2002

Keywords

• easy
• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Index entries for linear recurrences with constant coefficients, signature (14,-51,54).

Crossrefs

Cf. A001550, A001576, A034513, A001579, A074501 - A074580.

Programs

Magma

[2^n + 3^n + 9^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011

Mathematica

Table[2^n + 3^n + 9^n, {n, 0, 20}]
LinearRecurrence[{14,-51,54},{3,14,94},20] (* Harvey P. Dale, Nov 29 2019 *)

Formula

From Mohammad K. Azarian, Dec 27 2008: (Start)

G.f.: 1/(1-2*x) + 1/(1-3*x) + 1/(1-9*x).

E.g.f.: exp(2*x) + exp(3*x) + exp(9*x). (End)