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 A319632 #6 Oct 26 2018 12:50:18 %S A319632 1,1,3,5,11,17,35,53,100,154,275 %N A319632 Number of non-isomorphic weight-n antichains of (not necessarily distinct) sets whose dual is also an antichain of (not necessarily distinct) sets. %C A319632 The dual of a multiset partition has, for each vertex, one block consisting of the indices (or positions) of the blocks containing that vertex, counted with multiplicity. For example, the dual of {{1,2},{2,2}} is {{1},{1,2,2}}. %C A319632 The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices. %e A319632 Non-isomorphic representatives of the a(1) = 1 through a(4) = 11 set systems: %e A319632 1: {{1}} %e A319632 2: {{1,2}} %e A319632 {{1},{1}} %e A319632 {{1},{2}} %e A319632 3: {{1,2,3}} %e A319632 {{1},{2,3}} %e A319632 {{1},{1},{1}} %e A319632 {{1},{2},{2}} %e A319632 {{1},{2},{3}} %e A319632 4: {{1,2,3,4}} %e A319632 {{1},{2,3,4}} %e A319632 {{1,2},{1,2}} %e A319632 {{1,2},{3,4}} %e A319632 {{1},{1},{2,3}} %e A319632 {{1},{2},{3,4}} %e A319632 {{1},{1},{1},{1}} %e A319632 {{1},{1},{2},{2}} %e A319632 {{1},{2},{2},{2}} %e A319632 {{1},{2},{3},{3}} %e A319632 {{1},{2},{3},{4}} %Y A319632 Cf. A006126, A007716, A049311, A283877, A293606, A316980, A316983, A318099, A319558, A319616-A319646, A300913. %K A319632 nonn,more %O A319632 0,3 %A A319632 _Gus Wiseman_, Sep 25 2018