A129008 a(n) = (n^3 + n^2)*8^n.

16, 768, 18432, 327680, 4915200, 66060288, 822083584, 9663676416, 108716359680, 1181116006400, 12472585027584, 128642860449792, 1300722255659008, 12930256742645760, 126663739519795200, 1224979098644774912

Offset

1,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (32,-384,2048,-4096).

Formula

G.f.: 16*x*(1 + 16*x)/(1 - 8*x)^4. - Vincenzo Librandi, Feb 12 2013

a(n) = 32*a(n-1)-384*a(n-2)+2048*a(n-3)-4096*a(n-4). - Vincenzo Librandi, Feb 12 2013

Mathematica

CoefficientList[Series[16 (1 + 16 x)/(1 - 8 x)^4, {x, 0, 30}], x] (* Vincenzo Librandi, Feb 12 2013 *)

Prog

(Magma) [(n^3+n^2)*8^n: n in [1..25]]; // Vincenzo Librandi, Feb 12 2013
(Magma) I:=[16, 768, 18432, 327680]; [n le 4 select I[n] else 32*Self(n-1)-384*Self(n-2)+2048*Self(n-3)-4096*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Feb 12 2013

Crossrefs

Cf. A128796, A036289.

Sequence in context: A307923 A159375 A221527 * A134183 A042109 A221061

Adjacent sequences: A129005 A129006 A129007 * A129009 A129010 A129011

Keyword

nonn,easy

Author

Mohammad K. Azarian, May 01 2007

Status

approved