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 A351111 #6 Feb 04 2022 14:41:12 %S A351111 1,0,6,2,9436 %N A351111 Number of paths for a Racetrack car (using Moore neighborhood) with initial velocity zero, going from one corner to the diagonally opposite corner on an n X n grid, such that all positions are visited exactly once. %H A351111 Wikipedia, <a href="https://en.wikipedia.org/wiki/Racetrack_(game)">Racetrack</a> %e A351111 For n = 4 the following path and its reflection in the diagonal are the only solutions, so a(4) = 2. %e A351111 _ _ %e A351111 | | |_ %e A351111 |_ \ | %e A351111 _| |_| %Y A351111 Main diagonal of A351110. %Y A351111 Cf. A272445, A351041, A351107. %K A351111 nonn,more %O A351111 1,3 %A A351111 _Pontus von Brömssen_, Feb 01 2022