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 A318099 #40 Oct 26 2018 12:50:18
%S A318099 1,1,4,7,19,32,81,142,337,659,1564
%N A318099 Number of non-isomorphic weight-n antichains of (not necessarily distinct) multisets whose dual is also an antichain of (not necessarily distinct) multisets.
%C A318099 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 A318099 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 A318099 Non-isomorphic representatives of the a(1) = 1 through a(3) = 7 antichains:
%e A318099 1: {{1}}
%e A318099 2: {{1,1}}
%e A318099 {{1,2}}
%e A318099 {{1},{1}}
%e A318099 {{1},{2}}
%e A318099 3: {{1,1,1}}
%e A318099 {{1,2,3}}
%e A318099 {{1},{2,2}}
%e A318099 {{1},{2,3}}
%e A318099 {{1},{1},{1}}
%e A318099 {{1},{2},{2}}
%e A318099 {{1},{2},{3}}
%Y A318099 Cf. A000219, A006126, A007716, A049311, A059201, A283877, A306007, A316980, A316983, A319558, A319560, A319616-A319646, A300913.
%K A318099 nonn,more
%O A318099 0,3
%A A318099 _Gus Wiseman_, Sep 25 2018