A074613 a(n) = 4^n + 7^n.

2, 11, 65, 407, 2657, 17831, 121745, 839927, 5830337, 40615751, 283523825, 1981521047, 13858064417, 96956119271, 678491508305, 4748635251767, 33237225536897, 232647693856391, 1628482317387185, 11399170063280087

Offset: 0

Author

Robert G. Wilson v, Aug 26 2002

Keywords

• easy
• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (11,-28).

Crossrefs

Cf. A000051, A007689, A034472, A034474, A034491, A052539, A062394.

Cf. A062395, A062396, A063376, A063481, A074600 - A074624.

Programs

Magma

[4^n+7^n: n in [0..30]]; // G. C. Greubel, Mar 10 2023

Mathematica

Table[4^n + 7^n, {n, 0, 25}]
LinearRecurrence[{11,-28},{2,11},30] (* Harvey P. Dale, Oct 03 2013 *)

SageMath

[4^n+7^n for n in range(31)] # G. C. Greubel, Mar 10 2023

Formula

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

G.f.: 1/(1-4*x) + 1/(1-7*x).

E.g.f.: e^(4*x) + e^(7*x). (End)

a(n) = 11*a(n-1) - 28*a(n-2) with a(0)=2, a(1)=11. - Vincenzo Librandi, Jul 21 2010