A074619 a(n) = 6^n + 7^n.

2, 13, 85, 559, 3697, 24583, 164305, 1103479, 7444417, 50431303, 342941425, 2340123799, 16018069537, 109949704423, 756587236945, 5217746494519, 36054040477057, 249557173431943, 1729973554578865, 12008254925383639

Offset: 0

Author

Robert G. Wilson v, Aug 26 2002

Keywords

• easy
• nonn

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (13,-42).

Crossrefs

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

Programs

Magma

[7^n+6^n: n in [0..20]]; // Vincenzo Librandi, Jan 11 2013

Mathematica

Table[6^n + 7^n, {n, 0, 20}]
CoefficientList[Series[1/(1 - 6*x) + 1/(1 - 7*x), {x, 0, 20}], x] (* Vincenzo Librandi, Jan 11 2013 *)
LinearRecurrence[{13,-42},{2,13},30] (* Harvey P. Dale, Mar 30 2019 *)

PARI

a(n)=6^n+7^n \\ Charles R Greathouse IV, Oct 07 2015

Formula

G.f.: 1/(1-6*x)+1/(1-7*x). E.g.f.: e^(6*x)+e^(7*x). - Mohammad K. Azarian, Jan 11 2009

a(n)=13*a(n-1)-42*a(n-2) with a(0)=2, a(1)=13. - Vincenzo Librandi, Jul 21 2010