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

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for linear recurrences with constant coefficients, signature (15,-68,96).

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).

Mathematica

Table[3^n + 4^n + 8^n, {n, 0, 20}]

Prog

(Magma) [3^n + 4^n + 8^n: n in [0..30]]; // Vincenzo Librandi, Jun 13 2011

Crossrefs

Cf. A001550, A001576, A034513, A001579, A074501 - A074580.

Sequence in context: A231257 A074541 A368974 * A205576 A173695 A255688

Adjacent sequences: A074547 A074548 A074549 * A074551 A074552 A074553

Keyword

easy,nonn

Author

Robert G. Wilson v, Aug 23 2002

Status

approved