A074622 a(n) = 7^n + 8^n.

2, 15, 113, 855, 6497, 49575, 379793, 2920695, 22542017, 174571335, 1356217073, 10567261335, 82560763937, 646644824295, 5076269583953, 39931933598775, 314707907280257, 2484430327672455, 19642812107392433, 155514083261229015

Offset: 0

Author

Robert G. Wilson v, Aug 26 2002

Keywords

• easy
• nonn

Links

• Index entries for linear recurrences with constant coefficients, signature (15,-56).

Crossrefs

Cf. A000051, A034472, A052539, A034474, A062394, A034491, A062395, A062396, A007689, A063376, A063481, A074600..A074624.

Programs

Mathematica

Table[7^n + 8^n, {n, 0, 20}]
LinearRecurrence[{15,-56},{2,15},20] (* Harvey P. Dale, Jun 08 2022 *)

Formula

From Mohammad K. Azarian, Jan 11 2009: (Start)

G.f.: 1/(1-7*x) + 1/(1-8*x).

E.g.f.: e^(7*x) + e^(8*x). (End)

a(n) = 15*a(n-1) - 56*a(n-2) with a(0)=2, a(1)=15. - Vincenzo Librandi, Jul 21 2010