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 A327807 #4 Sep 26 2019 15:25:12 %S A327807 1,2,0,4,1,0,9,3,2,0,29,14,10,6,0,209,157,128,91,54,0 %N A327807 Triangle read by rows where T(n,k) is the number of unlabeled antichains of sets with n vertices and vertex-connectivity >= k. %C A327807 An antichain is a set of sets, none of which is a subset of any other. %C A327807 The vertex-connectivity of a set-system is the minimum number of vertices that must be removed (along with any resulting empty edges) to obtain a non-connected set-system or singleton. Note that this means a single node has vertex-connectivity 0. %e A327807 Triangle begins: %e A327807 1 %e A327807 2 0 %e A327807 4 1 0 %e A327807 9 3 2 0 %e A327807 29 14 10 6 0 %e A327807 209 157 128 91 54 0 %Y A327807 Column k = 0 is A306505. %Y A327807 Column k = 1 is A261006 (clutters), if we assume A261006(0) = A261006(1) = 0. %Y A327807 Column k = 2 is A305028 (blobs), if we assume A305028(0) = A305028(2) = 0. %Y A327807 Except for the first column, same as A327358 (the covering case). %Y A327807 The labeled version is A327806. %Y A327807 Cf. A014466, A293606, A326704, A326950, A327062, A327334, A327350, A327351, A327805, A327808. %K A327807 nonn,tabl,more %O A327807 0,2 %A A327807 _Gus Wiseman_, Sep 26 2019