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 A319641 #5 Sep 25 2018 20:48:03
%S A319641 1,1,3,5,11,18,41,70,159,323,778
%N A319641 Number of non-isomorphic weight-n antichains of distinct multisets whose dual is also an antichain of (not necessarily distinct) multisets.
%C A319641 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 A319641 The weight of a multiset partition is the sum of sizes of its parts. Weight is generally not the same as number of vertices.
%F A319641 Euler transform of A319628.
%e A319641 Non-isomorphic representatives of the a(1) = 1 through a(4) = 11 antichains:
%e A319641 1: {{1}}
%e A319641 2: {{1,1}}
%e A319641 {{1,2}}
%e A319641 {{1},{2}}
%e A319641 3: {{1,1,1}}
%e A319641 {{1,2,3}}
%e A319641 {{1},{2,2}}
%e A319641 {{1},{2,3}}
%e A319641 {{1},{2},{3}}
%e A319641 4: {{1,1,1,1}}
%e A319641 {{1,1,2,2}}
%e A319641 {{1,2,3,4}}
%e A319641 {{1},{2,2,2}}
%e A319641 {{1},{2,3,4}}
%e A319641 {{1,1},{2,2}}
%e A319641 {{1,2},{3,3}}
%e A319641 {{1,2},{3,4}}
%e A319641 {{1},{2},{3,3}}
%e A319641 {{1},{2},{3,4}}
%e A319641 {{1},{2},{3},{4}}
%Y A319641 Cf. A006126, A007716, A049311, A059201, A283877, A293606, A316980, A316983, A318099, A319558, A319616-A319646.
%K A319641 nonn,more
%O A319641 0,3
%A A319641 _Gus Wiseman_, Sep 25 2018