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 A327077 #7 Sep 01 2019 08:41:15 %S A327077 1,1,0,0,1,0,1,0,1,0,3,1,0,2,0,11,4,3,0,3,0,60,25,14,7,0,6,0,502,197, %T A327077 91,34,18,0,11,0,7403,2454,826,267,100,44,0,23,0,197442,48201,11383, %U A327077 2800,831,259,117,0,47,0 %N A327077 Triangle read by rows where T(n,k) is the number of unlabeled simple connected graphs with n vertices and k bridges. %C A327077 A bridge is an edge that, if removed without removing any incident vertices, disconnects the graph. Unlabeled connected graphs with no bridges are counted by A007146 (unlabeled graphs with spanning edge-connectivity >= 2). %H A327077 Gus Wiseman, <a href="/A327077/a327077.png">Unlabeled connected graphs with 5 vertices and k bridges.</a> %e A327077 Triangle begins: %e A327077 1 %e A327077 1 0 %e A327077 0 1 0 %e A327077 1 0 1 0 %e A327077 3 1 0 2 0 %e A327077 11 4 3 0 3 0 %e A327077 60 25 14 7 0 6 0 %e A327077 502 197 91 34 18 0 11 0 %e A327077 7403 2454 826 267 100 44 0 23 0 %e A327077 ... %Y A327077 The labeled version is A327072. %Y A327077 Row sums are A001349. %Y A327077 Row sums without the k = 0 column are A052446. %Y A327077 Column k = 0 is A007146, if we assume A007146(0) = 1. %Y A327077 Column k = 1 is A327074. %Y A327077 Column k = n - 1 is A000055. %Y A327077 Cf. A002494, A327071, A327073, A327108, A327109, A327111, A327130, A327144, A327145, A327146. %K A327077 nonn,more,tabl %O A327077 0,11 %A A327077 _Gus Wiseman_, Aug 26 2019 %E A327077 a(21)-a(54) from _Andrew Howroyd_, Aug 28 2019