A199560 (3*9^n+1)/2.

2, 14, 122, 1094, 9842, 88574, 797162, 7174454, 64570082, 581130734, 5230176602, 47071589414, 423644304722, 3812798742494, 34315188682442, 308836698141974, 2779530283277762, 25015772549499854, 225141952945498682

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (10,-9).

Formula

a(n) = 2*A066443(n).

a(n) = 9*a(n-1)-4.

a(n) = 10*a(n-1)-9*a(n-2).

G.f.: 2*(1-3*x)/((1-x)*(1-9*x)).

Mathematica

LinearRecurrence[{10, -9}, {2, 14}, 30] (* or *) NestList[9#-4&, 2, 30] (* Harvey P. Dale, May 30 2012 *)

Prog

(Magma) [(3*9^n+1)/2: n in [0..30]];

Crossrefs

Sequence in context: A351856 A155728 A267906 * A283184 A319536 A060468

Adjacent sequences: A199557 A199558 A199559 * A199561 A199562 A199563

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 08 2011

Status

approved