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 A175603 #24 Sep 08 2022 08:45:51
%S A175603 40,760,7960,79960,799960,7999960,79999960,799999960,7999999960,
%T A175603 79999999960,799999999960,7999999999960,79999999999960,
%U A175603 799999999999960,7999999999999960,79999999999999960,799999999999999960
%N A175603 a(n) = 8*(10^n-5).
%H A175603 Vincenzo Librandi, <a href="/A175603/b175603.txt">Table of n, a(n) for n = 1..100</a>
%H A175603 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (11,-10)
%F A175603 G.f.: 40*x*(1+8*x) / ( (10*x-1)*(x-1) ). - _R. J. Mathar_, Aug 24 2011
%t A175603 CoefficientList[Series[40 (1 + 8 x)/((10 x - 1) (x - 1)), {x, 0, 30}], x] (* _Vincenzo Librandi_, Oct 05 2014 *)
%t A175603 LinearRecurrence[{11,-10},{40,760},20] (* _Harvey P. Dale_, May 12 2022 *)
%o A175603 (Magma) [8*(10^n-5): n in [1..30]]; // _Vincenzo Librandi_, Oct 05 2014
%Y A175603 Equals 40 * A067272.
%K A175603 nonn,easy,less
%O A175603 1,1
%A A175603 _Vincenzo Librandi_ Nov 15 2010