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 A366338 #11 Nov 03 2023 17:01:26 %S A366338 1,1,8,44,509,7091 %N A366338 Number of free (4,2)-polyominoids with n cells, allowing right-angled (or hard) connections only. %C A366338 Two squares sharing an edge have a right-angled connection if they do not lie in the same plane. %C A366338 Connections that are not right-angled (flat connections) may occur, but the polyominoids considered here must be connected through right-angled connections only. %H A366338 Wikipedia, <a href="https://en.wikipedia.org/wiki/Polyominoid">Polyominoid</a>. %H A366338 <a href="/index/Pol#polyominoes">Index entries for sequences related to polyominoes</a>. %Y A366338 45th row of A366766. %Y A366338 Cf. A075679, A365654, A366334, A366339 (fixed), A366340. %K A366338 nonn,hard,more %O A366338 1,3 %A A366338 _Pontus von Brömssen_, Oct 07 2023