A074541 a(n) = 2^n + 6^n + 7^n.
3, 15, 89, 567, 3713, 24615, 164369, 1103607, 7444673, 50431815, 342942449, 2340125847, 16018073633, 109949712615, 756587253329, 5217746527287, 36054040542593, 249557173563015, 1729973554841009, 12008254925907927
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
- Index entries for linear recurrences with constant coefficients, signature (15,-68,84).
Programs
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Magma
[2^n + 6^n + 7^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
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Mathematica
Table[2^n + 6^n + 7^n, {n, 0, 20}]
Formula
From Mohammad K. Azarian, Dec 27 2008: (Start)
G.f.: 1/(1-2*x) + 1/(1-6*x) + 1/(1-7*x).
E.g.f.: exp(2*x) + exp(6*x) + exp(7*x). (End)