A128985 a(n) = (n^3 - n^2)*2^n.

0, 16, 144, 768, 3200, 11520, 37632, 114688, 331776, 921600, 2478080, 6488064, 16613376, 41746432, 103219200, 251658240, 606076928, 1443889152, 3406823424, 7969177600, 18496880640, 42630905856, 97626619904, 222264557568

Offset

1,2

Links

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

Index entries for linear recurrences with constant coefficients, signature (8,-24,32,-16).

Formula

G.f.: 16*x^2*(1 + x)/(1 - 2*x)^4. - Vincenzo Librandi, Feb 11 2013

a(n) = 8*a(n-1) -24*a(n-2) +32*a(n-3) -16*a(n-4). - Vincenzo Librandi, Feb 11 2013

Mathematica

CoefficientList[Series[16 x (1+x)/(1 - 2 x)^4, {x, 0, 30}], x] (* Vincenzo Librandi, Feb 11 2013 *)
Table[(n^3-n^2)2^n, {n, 30}] (* or *) LinearRecurrence[{8, -24, 32, -16}, {0, 16, 144, 768}, 30] (* Harvey P. Dale, Jul 06 2014  *)

Prog

(Magma) [(n^3-n^2)*2^n: n in [0..25]]; (* or *) I:=[0, 16, 144, 768]; [n le 4 select I[n] else 8*Self(n-1) - 24*Self(n-2) + 32*Self(n-3) - 16*Self(n-4): n in [1..25]]; // Vincenzo Librandi, Feb 11 2013
(PARI) a(n)=(n^3-n^2)<<n \\ Charles R Greathouse IV, Oct 07 2015

Crossrefs

Cf. A128796, A036289.

Sequence in context: A331741 A092820 A060300 * A341369 A004409 A319553

Adjacent sequences: A128982 A128983 A128984 * A128986 A128987 A128988

Keyword

nonn,easy

Author

Mohammad K. Azarian, Apr 30 2007

Extensions

Offset corrected by Mohammad K. Azarian, Nov 19 2008

Status

approved