%I #22 Sep 08 2022 08:45:30

%S 0,36,486,3888,24300,131220,642978,2939328,12754584,53144100,

%T 214347870,841802544,3233287044,12187005012,45199057050,165299408640,

%U 597144113712,2133912053412,7552375012566,26499561447600,92260315250460

%N a(n) = (n^3 - n^2)*3^n.

%H Vincenzo Librandi, <a href="/A128986/b128986.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (12,-54,108,-81).

%F G.f.: 18x^2(2+3x)/(1-3x)^4. - _R. J. Mathar_, Dec 19 2008

%F a(n) = 12*a(n-1) - 54*a(n-2) + 108*a(n-3) - 81*a(n-4). - _Vincenzo Librandi_, Feb 11 2013

%t LinearRecurrence[{12, -54, 108, -81}, {0, 36, 486, 3888}, 30] (* _Vincenzo Librandi_, Feb 11 2013 *)

%o (Magma) [(n^3 - n^2)*3^n: n in [1..25]]; // _Vincenzo Librandi_, Feb 11 2013

%Y Cf. A128796, A036289.

%K nonn,easy

%O 1,2

%A _Mohammad K. Azarian_, Apr 30 2007

%E Offset corrected by _Mohammad K. Azarian_, Nov 20 2008