A199761 (9*11^n+1)/5.

2, 20, 218, 2396, 26354, 289892, 3188810, 35076908, 385845986, 4244305844, 46687364282, 513561007100, 5649171078098, 62140881859076, 683549700449834, 7519046704948172, 82709513754429890, 909804651298728788, 10007851164286016666

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..900

Index entries for linear recurrences with constant coefficients, signature (12,-11).

Formula

a(n) = 11*a(n-1)-2.

a(n) = 12*a(n-1)-11*a(n-2).

G.f.: 2*(1-2*x)/((1-x)*(1-11*x)).

Mathematica

(9*11^Range[0, 20]+1)/5 (* or *) LinearRecurrence[{12, -11}, {2, 20}, 20] (* Harvey P. Dale, Mar 13 2024 *)

Prog

(Magma) [(9*11^n+1)/5: n in [0..30]];

Crossrefs

Sequence in context: A000906 A308945 A356853 * A214769 A227337 A127110

Adjacent sequences: A199758 A199759 A199760 * A199762 A199763 A199764

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 10 2011

Status

approved