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 A319645 #5 Sep 25 2018 20:48:32
%S A319645 1,1,1,2,3,4,7,9,16,22,38
%N A319645 Number of non-isomorphic weight-n antichains of distinct multisets whose dual is a chain of distinct multisets.
%C A319645 The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices. For example, the dual of {{1,2},{2,2}} is {{1},{1,2,2}}.
%C A319645 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 A319645 Non-isomorphic representatives of the a(1) = 1 through a(6) = 7 antichains:
%e A319645 1: {{1}}
%e A319645 2: {{1,1}}
%e A319645 3: {{1,1,1}}
%e A319645 {{1,2,2}}
%e A319645 4: {{1,1,1,1}}
%e A319645 {{1,2,2,2}}
%e A319645 {{1,2},{2,2}}
%e A319645 5: {{1,1,1,1,1}}
%e A319645 {{1,1,2,2,2}}
%e A319645 {{1,2,2,2,2}}
%e A319645 {{1,2},{2,2,2}}
%e A319645 6: {{1,1,1,1,1,1}}
%e A319645 {{1,1,2,2,2,2}}
%e A319645 {{1,2,2,2,2,2}}
%e A319645 {{1,2,2,3,3,3}}
%e A319645 {{1,2},{2,2,2,2}}
%e A319645 {{1,2,2},{2,2,2}}
%e A319645 {{1,2,3},{2,3,3}}
%Y A319645 Cf. A000219, A006126, A007716, A049311, A059201, A283877, A293606, A316980, A316983, A318099, A319616-A319646.
%K A319645 nonn,more
%O A319645 0,4
%A A319645 _Gus Wiseman_, Sep 25 2018