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 A015499 #8 Sep 08 2022 08:44:40
%S A015499 1,11,122,14884,19825488,290284795296,46750946852011392,
%T A015499 82822200907043005634304,1613970474494103062192651148288,
%U A015499 345968906493565448004393168763031894016,815776584570266460972904878145357549417415811072
%N A015499 a(0)=1, a(1)=11, a(n) = sum_{k=0}^{k=n-1} 11^k a(k).
%F A015499 a(n) = (11^(n-2) + 1) * a(n-1). - _Vincenzo Librandi_, Nov 11 2012
%o A015499 (Magma) I:=[1, 11, 122]; [n le 3 select I[n] else (11^(n-2)+1)*Self(n-1): n in [1..15]]; // _Vincenzo Librandi_, Nov 11 2012
%K A015499 nonn,easy
%O A015499 0,2
%A A015499 _Olivier Gérard_