A199491 (11*7^n+1)/2.

6, 39, 270, 1887, 13206, 92439, 647070, 4529487, 31706406, 221944839, 1553613870, 10875297087, 76127079606, 532889557239, 3730226900670, 26111588304687, 182781118132806, 1279467826929639, 8956274788507470, 62693923519552287

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)-3.

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

G.f.: 3*(2-3*x)/((1-x)*(1-7*x)).

Mathematica

(11*7^Range[0, 30]+1)/2 (* or *) LinearRecurrence[{8, -7}, {6, 39}, 30] (* Harvey P. Dale, Jan 23 2013 *)

Prog

(Magma) [(11*7^n+1)/2: n in [0..30]];

Crossrefs

Sequence in context: A370376 A357206 A370026 * A147961 A264232 A068765

Adjacent sequences: A199488 A199489 A199490 * A199492 A199493 A199494

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 07 2011

Status

approved