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 A024123 #19 Sep 08 2022 08:44:48
%S A024123 1,9,-412,-18683,-252144,-1853125,-9077696,-30353607,-34217728,
%T A024123 612579511,9000000000,97642052309,994840219648,9989395500627,
%U A024123 99979338953216,999961556640625,9999931280523264,99999881412123503
%N A024123 a(n) = 10^n - n^9.
%H A024123 Vincenzo Librandi, <a href="/A024123/b024123.txt">Table of n, a(n) for n = 0..300</a>
%H A024123 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (20,-145,570,-1410,2352,-2730,2220,-1245,460,-101,10).
%t A024123 Table[10^n-n^9,{n,0,30}] (* or *) LinearRecurrence[ {20,-145,570,-1410,2352,-2730,2220,-1245,460,-101,10},{1,9,-412,-18683,-252144,-1853125,-9077696,-30353607,-34217728,612579511,9000000000},30] (* _Harvey P. Dale_, Feb 06 2014 *)
%o A024123 (Magma) [10^n-n^9: n in [0..20]]; // _Vincenzo Librandi_, Jul 01 2011
%o A024123 (PARI) a(n)=10^n-n^9 \\ _Charles R Greathouse IV_, Jul 01 2011
%K A024123 sign,easy
%O A024123 0,2
%A A024123 _N. J. A. Sloane_