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 A325111 #34 Feb 16 2025 08:33:58 %S A325111 1,1,0,1,0,0,1,1,0,0,3,2,1,0,0,10,7,3,1,0,0,56,33,17,5,1,0,0,468,244, %T A325111 101,32,7,1,0,0,7123,2792,890,242,60,9,1,0,0,194066,52448,11468,2461, %U A325111 527,97,12,1,0,0,9743542,1690206,239728,35839,6056,1029,155,15,1,0,0 %N A325111 Triangle read by rows: T(n,k) is the number of simple connected graphs on n unlabeled nodes with k articulation vertices, (0 <= k <= n). %C A325111 Articulation vertices are also called cutpoints. These are vertices that when removed increase the component count of the graph. %H A325111 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ArticulationVertex.html">Articulation Vertex</a> %e A325111 Triangle begins: %e A325111 1; %e A325111 1 0; %e A325111 1, 0, 0; %e A325111 1, 1, 0, 0; %e A325111 3, 2, 1, 0, 0; %e A325111 10, 7, 3, 1, 0, 0; %e A325111 56, 33, 17, 5, 1, 0, 0; %e A325111 468, 244, 101, 32, 7, 1, 0, 0; %e A325111 7123, 2792, 890, 242, 60, 9, 1, 0, 0; %e A325111 ... %Y A325111 Columns k=0..5 are A002218(n>1), A241767, A241768, A241769, A241770, A241771. %Y A325111 Row sums are A001349. %Y A325111 Cf. A327077, A370064 (labeled version). %K A325111 nonn,tabl %O A325111 0,11 %A A325111 _Andrew Howroyd_, Sep 05 2019 %E A325111 Diagonal for k = n inserted by _Andrew Howroyd_, Feb 25 2024