A199420 a(n) = (5*7^n+1)/3.

2, 12, 82, 572, 4002, 28012, 196082, 1372572, 9608002, 67256012, 470792082, 3295544572, 23068812002, 161481684012, 1130371788082, 7912602516572, 55388217616002, 387717523312012, 2714022663184082, 18998158642288572

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (8,-7).

Formula

a(n) = 7*a(n-1)-2.

a(n) = 8*a(n-1)-7*a(n-2).

G.f.: 2*(1-2*x)/((1-x)*(1-7*x)).

Mathematica

LinearRecurrence[{8, -7}, {2, 12}, 30] (* Harvey P. Dale, Aug 25 2017 *)

Prog

(Magma) [(5*7^n+1)/3: n in [0..30]];

Crossrefs

Sequence in context: A340103 A055548 A092850 * A235348 A052864 A355378

Adjacent sequences: A199417 A199418 A199419 * A199421 A199422 A199423

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 07 2011

Status

approved