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 A199030 #18 Mar 20 2023 05:06:49 %S A199030 9,109,1209,13309,146409,1610509,17715609,194871709,2143588809, %T A199030 23579476909,259374246009,2853116706109,31384283767209, %U A199030 345227121439309,3797498335832409,41772481694156509,459497298635721609,5054470284992937709 %N A199030 a(n) = 10*11^n-1. %H A199030 Vincenzo Librandi, <a href="/A199030/b199030.txt">Table of n, a(n) for n = 0..900</a> %H A199030 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (12,-11). %F A199030 a(n) = 11*a(n-1)+10. %F A199030 a(n) = 12*a(n-1)-11*a(n-2). %F A199030 G.f.: (9+x)/((1-x)*(1-11*x)). - _Bruno Berselli_, Nov 03 2011 %o A199030 (Magma) [10*11^n-1: n in [0..20]]; %K A199030 nonn,easy %O A199030 0,1 %A A199030 _Vincenzo Librandi_, Nov 03 2011