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 A211943 #14 Feb 22 2021 13:23:18 %S A211943 5,3,15,33,106,361,1012,3859,11655,43431 %N A211943 Number of distinct regular languages over 3-ary alphabet, whose minimum regular expression has reverse Polish length n. %H A211943 Hermann Gruber, Jonathan Lee, and Jeffrey Shallit, <a href="http://arxiv.org/abs/1204.4982">Enumerating regular expressions and their languages</a>, arXiv:1204.4982v1 [cs.FL], 2012. %K A211943 nonn,hard %O A211943 1,1 %A A211943 _Hermann Gruber_, Apr 26 2012