A129004 (n^3+n^2)*4^n.

8, 192, 2304, 20480, 153600, 1032192, 6422528, 37748736, 212336640, 1153433600, 6090129408, 31406948352, 158779572224, 789200240640, 3865470566400, 18691697672192, 89369679495168, 423037098786816

Offset

1,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (16,-96,256,-256).

Formula

G.f.: 8*x*(1+8*x)/(1-4*x)^4. [R. J. Mathar, Dec 19 2008]

a(1)=8, a(2)=192, a(3)=2304, a(4)=20480, a(n)=16*a(n-1)-96*a(n-2)+ 256*a(n-3)-256*a(n-4). [Harvey P. Dale, May 12 2011]

a(n) = 8*(A038846(n-1)+8*A038846(n-2)), with A038846(-1)=0. [Bruno Berselli, Feb 12 2013]

Mathematica

Table[(n^3+n^2)4^n, {n, 20}] (* or *) LinearRecurrence[{16, -96, 256, -256}, {8, 192, 2304, 20480}, 20] (* Harvey P. Dale, May 12 2011 *)

Prog

(Magma) [(n^3+n^2)*4^n: n in [1..25]]; // Vincenzo Librandi, Feb 12 2013

Crossrefs

Cf. A036289, A038846, A128796.

Sequence in context: A251669 A158654 A275995 * A267948 A339487 A189537

Adjacent sequences: A129001 A129002 A129003 * A129005 A129006 A129007

Keyword

nonn,easy

Author

Mohammad K. Azarian, May 01 2007

Status

approved