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 A121193 #14 Jun 02 2025 00:29:51 %S A121193 1,2,5,17,55,206,718 %N A121193 Erroneous version of A159866. %H A121193 Livio Zucca, <a href="http://www.iread.it/lz/polymultiforms2.html">PolyMultiForms</a> %K A121193 dead %O A121193 1,2 %A A121193 _N. J. A. Sloane_, Aug 17 2006