A199113 a(n) = (11*3^n+1)/2.

6, 17, 50, 149, 446, 1337, 4010, 12029, 36086, 108257, 324770, 974309, 2922926, 8768777, 26306330, 78918989, 236756966, 710270897, 2130812690, 6392438069, 19177314206, 57531942617, 172595827850, 517787483549, 1553362450646, 4660087351937

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (4,-3).

Formula

a(n) = 3*a(n-1)-1.

a(n) = 4*a(n-1)-3*a(n-2).

G.f.: (6-7*x)/((1-x)*(1-3*x)). - Bruno Berselli, Nov 04 2011

Mathematica

LinearRecurrence[{4, -3}, {6, 17}, 30] (* or *) (11 3^Range[0, 30]+1)/2 (* Harvey P. Dale, Mar 25 2012 *)

Prog

(Magma) [(11*3^n+1)/2: n in [0..30]];

Crossrefs

Sequence in context: A054492 A128525 A083334 * A297297 A241352 A239796

Adjacent sequences: A199110 A199111 A199112 * A199114 A199115 A199116

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 04 2011

Status

approved