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 A339071 #23 Jan 31 2025 11:39:17 %S A339071 0,1,0,1,0,1,1,1,0,1,2,3,2,1,1,0,1,3,9,14,12,8,5,2,1,1,0,1,4,20,50,82, %T A339071 94,81,59,38,20,10,5,2,1,1,0,1,6,40,161,429,780,1076,1197,1114,885, %U A339071 622,386,215,112,55,24,11,5,2,1,1,0,1,7,70,433,1729,4796 %N A339071 Triangle read by rows: T(n,k) is the number of unlabeled simple nonseparable (or 2-connected) graphs with n nodes and k edges (n >= 1, n-1 <= k <= n*(n-1)/2). %H A339071 Andrew Howroyd, <a href="/A339071/b339071.txt">Table of n, a(n) for n = 1..576</a> (rows 1..16, extracted from Robinson's tables) %H A339071 R. W. Robinson, <a href="http://web.archive.org/web/20041220072855/http://www.cs.uga.edu/~rwr/publications/tables.pdf">Tables of 2-Connected and 3-Connected Graphs by Nodes and Edges</a>, Table IV, pages 4-9. %H A339071 R. W. Robinson, <a href="http://cobweb.cs.uga.edu/~rwr/publications/tables.pdf">Tables</a> %H A339071 R. W. Robinson, <a href="/A002218/a002218_2.pdf">Tables</a> [Local copy, with permission] %e A339071 Triangle T(n,k) begins: %e A339071 ====================================================== %e A339071 n/k | 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 %e A339071 ----+------------------------------------------------- %e A339071 1 | 0; %e A339071 2 | 1; %e A339071 3 | 0, 1; %e A339071 4 | 0, 1, 1, 1; %e A339071 5 | 0, 1, 2, 3, 2, 1, 1; %e A339071 6 | 0, 1, 3, 9, 14, 12, 8, 5, 2, 1, 1; %e A339071 ... %Y A339071 Row sums are A002218. %Y A339071 Column sums are A010355. %Y A339071 Cf. A054923, A054924, A123534, A339070 (transpose), A339072. %K A339071 nonn,tabf %O A339071 1,11 %A A339071 _Andrew Howroyd_, Nov 23 2020