A074552 a(n) = 3^n + 5^n + 7^n.

3, 15, 83, 495, 3107, 20175, 134003, 903855, 6161987, 42326415, 292299923, 2026332015, 14085959267, 98111307855, 684331371443, 4778093436975, 33385561506947, 233393582580495, 1632228682596563, 11417969833962735

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,-71,105).

Formula

From Mohammad K. Azarian, Dec 30 2008: (Start)

G.f.: 1/(1-3*x) + 1/(1-5*x) + 1/(1-7*x).

E.g.f.: exp(3*x) + exp(5*x) + exp(7*x). (End)

a(n) = 15*a(n-1) - 71*a(n-2) + 105*a(n-3).

Mathematica

Table[3^n + 5^n + 7^n, {n, 0, 20}]
LinearRecurrence[{15, -71, 105}, {3, 15, 83}, 20] (* Harvey P. Dale, Jul 16 2020 *)

Prog

(Magma) [3^n + 5^n + 7^n: n in [0..30]]; // Vincenzo Librandi, Jun 13 2011

Crossrefs

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

Sequence in context: A026019 A354660 A118356 * A193658 A195885 A115910

Adjacent sequences: A074549 A074550 A074551 * A074553 A074554 A074555

Keyword

easy,nonn

Author

Robert G. Wilson v, Aug 23 2002

Status

approved