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 A322396 #18 Feb 16 2025 08:33:57
%S A322396 1,1,1,2,5,18,98,779,10589,255790,11633297,1004417286,163944008107,
%T A322396 50324877640599,29001521193534445,31396727025729968365,
%U A322396 63969154112074956299242,245871360738448777028919520,1787330701747389106609369225312,24636017249593067184544456944967278
%N A322396 Number of unlabeled simple connected graphs with n vertices whose bridges are all leaves, meaning at least one end of any bridge is an endpoint of the graph.
%H A322396 Andrew Howroyd, <a href="/A322396/b322396.txt">Table of n, a(n) for n = 0..25</a>
%H A322396 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphBridge.html">Graph Bridge</a>
%H A322396 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Endpoint.html">Endpoint</a>
%H A322396 Gus Wiseman, <a href="/A322396/a322396.png">The a(5) = 18 simple connected graphs whose bridges are all leaves.</a>
%o A322396 (PARI) \\ See A004115 for graphsSeries and A339645 for combinatorial species functions.
%o A322396 bridgelessGraphs(n)={my(gc=sLog(graphsSeries(n)), gcr=sPoint(gc)); sSolve( gc + gcr^2/2 - sRaise(gcr,2)/2, x*sv(1)*sExp(gcr) )}
%o A322396 cycleIndexSeries(n)={1+sSubstOp(bridgelessGraphs(n), symGroupSeries(n))}
%o A322396 NumUnlabeledObjsSeq(cycleIndexSeries(15)) \\ _Andrew Howroyd_, Dec 31 2020
%Y A322396 Cf. A001187, A006125, A007146, A013922, A054921, A095983, A322338, A322394, A322395.
%K A322396 nonn
%O A322396 0,4
%A A322396 _Gus Wiseman_, Dec 06 2018
%E A322396 a(6)-a(10) from _Andrew Howroyd_, Dec 08 2018
%E A322396 Terms a(11) and beyond from _Andrew Howroyd_, Dec 31 2020