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 A024051 #15 Sep 08 2022 08:44:48
%S A024051 1,4,21,116,609,3100,15589,78076,390561,1953044,9765525,48828004,
%T A024051 244140481,1220702956,6103515429,30517577900,152587890369,
%U A024051 762939452836,3814697265301,19073486327764,95367431640225
%N A024051 a(n) = 5^n - n^2.
%H A024051 Vincenzo Librandi, <a href="/A024051/b024051.txt">Table of n, a(n) for n = 0..300</a>
%H A024051 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (8, -18, 16, -5).
%F A024051 a(n) = 8*a(n-1) - 18*a(n-2) + 16*a(n-3) - 5*a(n-4).
%t A024051 Table[5^n-n^2,{n,0,20}] (* or *) LinearRecurrence[{8,-18,16,-5},{1,4,21,116},30] (* _Harvey P. Dale_, Nov 22 2012 *)
%o A024051 (Magma) [5^n-n^2: n in [0..35]]; // _Vincenzo Librandi_, Jun 12 2011
%K A024051 nonn,easy
%O A024051 0,2
%A A024051 _N. J. A. Sloane_