A128987 a(n) = (n^3 - n^2)*4^n.

0, 64, 1152, 12288, 102400, 737280, 4816896, 29360128, 169869312, 943718400, 5075107840, 26575110144, 136096776192, 683973541888, 3382286745600, 16492674416640, 79439715106816, 378506877861888, 1786156639322112

Offset: 1

Author

Mohammad K. Azarian, Apr 30 2007

Keywords

• nonn
• easy

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).

Crossrefs

Cf. A128796, A036289.

Programs

Magma

[(n^3 - n^2)*4^n: n in [1..25]]; // Vincenzo Librandi, Feb 11 2013

Mathematica

LinearRecurrence[{16, -96, 256, -256}, {0, 64, 1152, 12288}, 30] (* Vincenzo Librandi, Feb 11 2013 *)

Formula

G.f.: 64x^2(1+2x)/(1-4x)^4. - R. J. Mathar, Dec 19 2008

a(n) = 16*a(n-1) -96*a(n-2) +256*a(n-3)-256*a(n-4). - Vincenzo Librandi, Feb 11 2013

Extensions

Offset corrected by Mohammad K. Azarian, Nov 20 2008