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 A362908 #9 May 10 2023 12:47:36 %S A362908 0,0,0,1,4,17,72,323,1639,9203 %N A362908 Number of graphs on n unlabeled nodes with treewidth 2. %H A362908 Wikipedia, <a href="http://en.wikipedia.org/wiki/Treewidth">Treewidth</a>. %e A362908 There is a single graph of treewidth 2 on 3 vertices, which is the complete graph. %o A362908 (SageMath) [sum(1 for g in graphs(n) if g.treewidth() == 2) for n in range(9)] %Y A362908 Column 2 of A263294. %K A362908 nonn,more %O A362908 0,5 %A A362908 _Martin Rubey_, May 09 2023