A129006 (n^3+n^2)*6^n.

12, 432, 7776, 103680, 1166400, 11757312, 109734912, 967458816, 8162933760, 66512793600, 526781325312, 4074936532992, 30901602041856, 230390642442240, 1692665944473600, 12277470317248512, 88052482431516672

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (24,-216,864,-1296).

Formula

G.f.: 12*x*(1+12*x)/(1-6*x)^4. - Vincenzo Librandi, Feb 12 2013

a(n) = 24*a(n-1)-216*a(n-2)+864*a(n-3)-1296*a(n-4). - Vincenzo Librandi, Feb 12 2013

Mathematica

CoefficientList[Series[12 (1 + 12 x)/(1 - 6 x)^4, {x, 0, 30}], x] (* Vincenzo Librandi, Feb 12 2013 *)
Table[(n^3+n^2)6^n, {n, 20}] (* or *) LinearRecurrence[{24, -216, 864, -1296}, {12, 432, 7776, 103680}, 20] (* Harvey P. Dale, Aug 16 2014 *)

Prog

(Magma) [(n^3+n^2)*6^n: n in [1..25]]; /* or */ I:=[12, 432, 7776, 103680]; [n le 4 select I[n] else 24*Self(n-1)-216*Self(n-2)+864*Self(n-3)-1296*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Feb 12 2013

Crossrefs

Cf. A128796, A036289.

Sequence in context: A262858 A123778 A347795 * A067429 A054913 A221955

Adjacent sequences: A129003 A129004 A129005 * A129007 A129008 A129009

Keyword

nonn,easy

Author

Mohammad K. Azarian, May 01 2007

Status

approved