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 A322151 #5 Nov 28 2018 20:57:09
%S A322151 1,2,5,27,216,2311,30988,499919,9431026,203743252,4960335470,
%T A322151 134382267082,4009794148101,130668970606412,4617468180528235,
%U A322151 175867725701333896,7182126650899080024,313063334893103361130,14507460736615554141354,712192629608088061633746
%N A322151 Number of labeled connected graphs with loops with n edges (the vertices are {1,2,...,k} for some k).
%H A322151 Andrew Howroyd, <a href="/A322151/b322151.txt">Table of n, a(n) for n = 0..200</a>
%t A322151 multsubs[set_,k_]:=If[k==0,{{}},Join@@Table[Prepend[#,set[[i]]]&/@multsubs[Drop[set,i-1],k-1],{i,Length[set]}]];
%t A322151 csm[s_]:=With[{c=Select[Tuples[Range[Length[s]],2],And[OrderedQ[#],UnsameQ@@#,Length[Intersection@@s[[#]]]>0]&]},If[c=={},s,csm[Union[Append[Delete[s,List/@c[[1]]],Union@@s[[c[[1]]]]]]]]];
%t A322151 Table[Length[Select[Subsets[multsubs[Range[n+1],2],{n}],And[Union@@#==Range[Max@@Union@@#],Length[csm[#]]==1]&]],{n,5}]
%o A322151 (PARI)
%o A322151 Connected(v)={my(u=vector(#v)); for(n=1, #u, u[n]=v[n] - sum(k=1, n-1, binomial(n-1, k)*v[k]*u[n-k])); u}
%o A322151 seq(n)={Vec(vecsum(Connected(vector(2*n, j, (1 + x + O(x*x^n))^binomial(j+1,2)))))} \\ _Andrew Howroyd_, Nov 28 2018
%Y A322151 Row sums of A322147. The unlabeled version is A191970.
%Y A322151 Cf. A000664, A002905, A007718, A013922, A054923, A057500, A191646, A291842 (planar case), A321254, A322114, A322115.
%K A322151 nonn
%O A322151 0,2
%A A322151 _Gus Wiseman_, Nov 28 2018
%E A322151 Terms a(7) and beyond from _Andrew Howroyd_, Nov 28 2018