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 A321134 #8 Jan 11 2019 20:35:22
%S A321134 1,1,1,2,7,406,505635
%N A321134 Number of uniform hypergraphs spanning n vertices where every two vertices appear together in some edge.
%C A321134 A hypergraph is uniform if all edges have the same size.
%e A321134 The a(4) = 7 hypergraphs:
%e A321134 {{1,2,3,4}}
%e A321134 {{1,2,3},{1,2,4},{1,3,4}}
%e A321134 {{1,2,3},{1,2,4},{2,3,4}}
%e A321134 {{1,2,3},{1,3,4},{2,3,4}}
%e A321134 {{1,2,4},{1,3,4},{2,3,4}}
%e A321134 {{1,2,3},{1,2,4},{1,3,4},{2,3,4}}
%e A321134 {{1,2},{1,3},{1,4},{2,3},{2,4},{3,4}}
%t A321134 Table[Sum[Length[Select[Subsets[Subsets[Range[n],{k}]],And[Union@@#==Range[n],Length[Union@@(Subsets[#,{2}]&/@#)]==Binomial[n,2]]&]],{k,1,n}],{n,1,6}]
%Y A321134 Row sums of A320606.
%Y A321134 Cf. A058891, A299353, A302394, A306021, A319189, A320444.
%K A321134 nonn,more
%O A321134 0,4
%A A321134 _Gus Wiseman_, Jan 10 2019