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 A128988 #25 Sep 08 2022 08:45:30
%S A128988 0,100,2250,30000,312500,2812500,22968750,175000000,1265625000,
%T A128988 8789062500,59082031250,386718750000,2475585937500,15551757812500,
%U A128988 96130371093750,585937500000000,3527832031250000,21011352539062500
%N A128988 a(n) = (n^3 - n^2)*5^n.
%H A128988 Vincenzo Librandi, <a href="/A128988/b128988.txt">Table of n, a(n) for n = 1..1000</a>
%H A128988 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (20,-150,500,-625).
%F A128988 a(1)=0, a(2)=100, a(3)=2250, a(4)=30000, a(n)=20*a(n-1)- 150*a(n-2)+ 500*a(n-3)- 625*a(n-4). - _Harvey P. Dale_, Oct 25 2011
%F A128988 G.f.: (50*(5*x^2+2*x))/(5*x-1)^4. - _Harvey P. Dale_, Oct 25 2011
%t A128988 Table[(n^3-n^2)5^n,{n,20}] (* or *) LinearRecurrence[{20,-150,500,-625},{0,100,2250,30000},20]
%o A128988 (Magma) [(n^3-n^2)*5^n: n in [1..30]]; // _Vincenzo Librandi_, Oct 26 2011
%Y A128988 Cf. A128796; A036289.
%K A128988 nonn
%O A128988 1,2
%A A128988 _Mohammad K. Azarian_, Apr 30 2007
%E A128988 Offset corrected by _Mohammad K. Azarian_, Nov 19 2008