A074561 a(n) = 4^n + 5^n + 6^n.
3, 15, 77, 405, 2177, 11925, 66377, 374445, 2135777, 12292965, 71280377, 415819485, 2437700177, 14348506005, 84736115177, 501776304525, 2977992765377, 17706778767045, 105443373410777, 628708104245565
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (15,-74,120).
Programs
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Magma
[4^n + 5^n + 6^n: n in [0..20]]; // Vincenzo Librandi, Aug 24 2011
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Mathematica
Table[4^n + 5^n + 6^n, {n, 0, 19}]
Formula
From Mohammad K. Azarian, Dec 30 2008: (Start)
G.f.: 1/(1-4*x) + 1/(1-5*x) + 1/(1-6*x).
E.g.f.: exp(4*x) + exp(5*x) + exp(6*x). (End)