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

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (13,-42).

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

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 *)

Prog

(Magma) [7^n+6^n: n in [0..20]]; // Vincenzo Librandi, Jan 11 2013
(PARI) a(n)=6^n+7^n \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

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

Sequence in context: A285795 A134148 A164035 * A162275 A092070 A091116

Adjacent sequences: A074616 A074617 A074618 * A074620 A074621 A074622

Keyword

easy,nonn,changed

Author

Robert G. Wilson v, Aug 26 2002

Status

approved