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 A319558 #9 Sep 24 2018 08:57:47
%S A319558 1,1,3,7,21,55,169,496,1582,5080,17073
%N A319558 The squarefree dual of a multiset partition has, for each vertex, one block consisting of the indices (or positions) of the blocks containing that vertex, counted without multiplicity. Then a(n) is the number of non-isomorphic multiset partitions of weight n whose squarefree dual is strict (no repeated blocks).
%C A319558 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 A319558 Non-isomorphic representatives of the a(1) = 1, a(2) = 3, and a(3) = 7 multiset partitions:
%e A319558 1: {{1}}
%e A319558 2: {{1,1}}
%e A319558 {{1},{1}}
%e A319558 {{1},{2}}
%e A319558 3: {{1,1,1}}
%e A319558 {{1},{1,1}}
%e A319558 {{1},{2,2}}
%e A319558 {{2},{1,2}}
%e A319558 {{1},{1},{1}}
%e A319558 {{1},{2},{2}}
%e A319558 {{1},{2},{3}}
%Y A319558 Cf. A007716, A007718, A049311, A053419, A056156, A059201, A283877, A316980.
%Y A319558 Cf. A319557, A319559, A319560, A319564, A319565, A319566, A319567.
%K A319558 nonn,more
%O A319558 0,3
%A A319558 _Gus Wiseman_, Sep 23 2018