This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A128989 #33 Mar 08 2025 09:35:19
%S A128989 0,144,3888,62208,777600,8398080,82301184,752467968,6530347008,
%T A128989 54419558400,438984437760,3448023220224,26487087464448,
%U A128989 199671890116608,1481082701414400,10833062044631040,78268873272459264,559392241329635328,3959619590588203008,27786804144478617600
%N A128989 a(n) = (n^3 - n^2)*6^n.
%H A128989 Vincenzo Librandi, <a href="/A128989/b128989.txt">Table of n, a(n) for n = 1..1000</a>
%H A128989 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (24,-216,864,-1296).
%F A128989 From _Vincenzo Librandi_, Feb 12 2013: (Start)
%F A128989 G.f.: 144*x^2*(1+3*x)/(1-6*x)^4.
%F A128989 a(n) = 24*a(n-1)-216*a(n-2)+864*a(n-3)-1296*a(n-4). (End)
%F A128989 E.g.f.: 72*exp(6*x)*x^2*(1 + 3*x). - _Stefano Spezia_, Mar 08 2025
%t A128989 CoefficientList[Series[144 x (1 + 3 x)/(1 - 6 x)^4, {x, 0, 30}], x] (* _Vincenzo Librandi_, Feb 12 2013 *)
%t A128989 Table[(n^3-n^2)6^n,{n,20}] (* or *) LinearRecurrence[{24,-216,864,-1296},{0,144,3888,62208},20] (* _Harvey P. Dale_, Apr 29 2019 *)
%o A128989 (Magma) [(n^3-n^2)*6^n: n in [1..25]]; // _Vincenzo Librandi_, Feb 12 2013
%o A128989 (Magma) I:=[0,144,3888,62208]; [n le 4 select I[n] else 24*Self(n-1)-216*Self(n-2)+864*Self(n-3)-1296*Self(n-4): n in [1..25]]; // _Vincenzo Librandi_, Feb 12 2013
%Y A128989 Cf. A128796, A036289.
%K A128989 nonn,easy
%O A128989 1,2
%A A128989 _Mohammad K. Azarian_, Apr 30 2007
%E A128989 Offset corrected by _Mohammad K. Azarian_, Nov 20 2008