A074550 a(n) = 3^n + 4^n + 8^n.
3, 15, 89, 603, 4433, 34035, 266969, 2115723, 16849313, 134499555, 1074849449, 8594306043, 68736785393, 549824517075, 4398319729529, 35185460179563, 281479314724673, 2251817122694595, 18014467616379209, 144115464116024283
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
- Index entries for linear recurrences with constant coefficients, signature (15,-68,96).
Programs
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Magma
[3^n + 4^n + 8^n: n in [0..30]]; // Vincenzo Librandi, Jun 13 2011
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Mathematica
Table[3^n + 4^n + 8^n, {n, 0, 20}]
Formula
From Mohammad K. Azarian, Dec 28 2008: (Start)
G.f.: 1/(1-3*x) + 1/(1-4*x) + 1/(1-8*x).
E.g.f.: exp(3*x) + exp(4*x) + exp(8*x). (End)
a(n) = 15*a(n-1) - 68*a(n-2) + 96*a(n-3).