A074544 a(n) = 2^n + 7^n + 8^n.
3, 17, 117, 863, 6513, 49607, 379857, 2920823, 22542273, 174571847, 1356218097, 10567263383, 82560768033, 646644832487, 5076269600337, 39931933631543, 314707907345793, 2484430327803527, 19642812107654577, 155514083261753303
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
- Index entries for linear recurrences with constant coefficients, signature (17,-86,112).
Programs
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Magma
[ 2^n + 7^n + 8^n: n in [0..30]]; // Vincenzo Librandi, Jun 13 2011
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Mathematica
Table[2^n + 7^n + 8^n, {n, 0, 20}]
Formula
From Mohammad K. Azarian, Dec 28 2008: (Start)
G.f.: 1/(1-2*x) + 1/(1-7*x) + 1/(1-8*x).
E.g.f.: exp(2*x) + exp(7*x) + exp(8*x). (End)
a(n) = 17*a(n-1) - 86*a(n-2) + 112*a(n-3).