A074555 a(n) = 3^n + 6^n + 7^n.
3, 16, 94, 586, 3778, 24826, 165034, 1105666, 7450978, 50450986, 343000474, 2340300946, 16018600978, 109951298746, 756592019914, 5217760843426, 36054083523778, 249557302572106, 1729973941999354, 12008256087645106
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (16,-81,126).
Programs
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Magma
[3^n + 6^n + 7^n: n in [0..20]]; // Vincenzo Librandi, Aug 24 2011
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Mathematica
Table[3^n + 6^n + 7^n, {n, 0, 20}]
Formula
From Mohammad K. Azarian, Dec 30 2008: (Start)
G.f.: 1/(1-3*x) + 1/(1-6*x) + 1/(1-7*x).
E.g.f.: exp(3*x) + exp(6*x) + exp(7*x). (End)