A074559 a(n) = 3^n + 7^n + 9^n.

3, 19, 139, 1099, 9043, 76099, 649819, 5608699, 48818083, 427793779, 3769318699, 33358563499, 296271355123, 2638756433059, 23555020310779, 210638707953499, 1886253162468163, 16909812342793939, 151723049282330059

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (19,-111,189).

Formula

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

G.f.: 1/(1-3*x) + 1/(1-7*x) + 1/(1-9*x).

E.g.f.: exp(3*x) + exp(7*x) + exp(9*x). (End)

a(n) = 19*a(n-1) - 111*a(n-2) + 189*a(n-3). - Wesley Ivan Hurt, Apr 11 2023

Mathematica

Table[3^n + 7^n + 9^n, {n, 0, 20}]

Prog

(Magma) [3^n + 7^n + 9^n: n in [0..20]]; // Vincenzo Librandi, Aug 24 2011

Crossrefs

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

Sequence in context: A156894 A221374 A073515 * A027314 A025571 A221266

Adjacent sequences: A074556 A074557 A074558 * A074560 A074561 A074562

Keyword

easy,nonn

Author

Robert G. Wilson v, Aug 23 2002

Status

approved