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 A294525 #18 Feb 16 2025 08:33:51 %S A294525 1,0,1,1,0,1,2,2,0,2,8,4,4,0,5,29,19,18,18,0,28,180,84,119,118,129,0, %T A294525 223,1463,821,1055,1426,1390,1811,0,3151,20093,12485,17297,24853, %U A294525 29987,30515,46177,0,79673,474063,343572,486446,763319,1015304,1247381,1296986,2235630,0,3853870 %N A294525 Triangle read by rows: T(n,k) is the number of simple connected graphs on n nodes with k center nodes. %C A294525 The column sequences A052437-A052441 also include disconnected graphs. Disconnected graphs have an infinite radius and all nodes are considered a part of the center. %H A294525 Sean A. Irvine, <a href="/A294525/b294525.txt">Table of n, a(n) for n = 1..78</a> %H A294525 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphCenter.html">Graph Center</a> %e A294525 Triangle begins: %e A294525 : 1; %e A294525 : 0, 1; %e A294525 : 1, 0, 1; %e A294525 : 2, 2, 0, 2; %e A294525 : 8, 4, 4, 0, 5; %e A294525 : 29, 19, 18, 18, 0, 28; %e A294525 : 180, 84, 119, 118, 129, 0, 223; %e A294525 : 1463, 821, 1055, 1426, 1390, 1811, 0, 3151; %e A294525 ... %Y A294525 Columns 1..5 except first term are A052437, A052438, A052439, A052440, A052441. %Y A294525 Row sums give A001349. %K A294525 nonn,tabl %O A294525 1,7 %A A294525 _Andrew Howroyd_, Nov 01 2017