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 A263294 #44 Feb 03 2025 15:56:53 %S A263294 1,1,1,1,2,1,1,5,4,1,1,9,17,6,1,1,19,72,53,10,1,1,36,323,501,168,14,1, %T A263294 1,75,1639,5889,4163,557,21,1,1,152,9203,81786,138923,42596,1977,29,1 %N A263294 Triangle read by rows: T(n,k) is the number of unlabeled simple graphs with n vertices and treewidth k. %C A263294 A graph without edges has treewidth 0, any other forest has treewidth 1, any other series parallel graph has treewidth 2. - _Martin Rubey_, May 10 2023 %H A263294 FindStat - Combinatorial Statistic Finder, <a href="http://www.findstat.org/StatisticsDatabase/St000272">The treewidth of a graph</a>. %H A263294 Wikipedia, <a href="https://en.wikipedia.org/wiki/Treewidth">Treewidth</a> %e A263294 Triangle begins: %e A263294 1; %e A263294 1, 1; %e A263294 1, 2, 1; %e A263294 1, 5, 4, 1; %e A263294 1, 9, 17, 6, 1; %e A263294 1, 19, 72, 53, 10, 1; %e A263294 1, 36, 323, 501, 168, 14, 1; %e A263294 1, 75, 1639, 5889, 4163, 557, 21, 1; %e A263294 1, 152, 9203, 81786, 138923, 42596, 1977, 29, 1; %e A263294 ... %Y A263294 Columns k=2..3 are A362908, A362907. %Y A263294 Partial row sums include A000012, A005195, A000041. %Y A263294 Row sums are A000088. %Y A263294 T(n,n-2) = A000065(n). %K A263294 nonn,tabl,more %O A263294 1,5 %A A263294 _Christian Stump_, Oct 13 2015 %E A263294 Corrected and extended by _Martin Rubey_, May 10 2023