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 A323789 #5 Jan 28 2019 08:07:05
%S A323789 1,1,4,15,64,269,1310,6460
%N A323789 Number of non-isomorphic weight-n sets of sets of multisets.
%C A323789 Also the number of non-isomorphic strict multiset partitions, with strict parts, of multiset partitions of weight n.
%C A323789 All sets and multisets must be finite, and only the outermost may be empty.
%C A323789 The weight of an atom is 1, and the weight of a multiset is the sum of weights of its elements, counting multiplicity.
%e A323789 Non-isomorphic representatives of the a(1) = 1 through a(3) = 15 multiset partition partitions:
%e A323789 {{1}} {{11}} {{111}}
%e A323789 {{12}} {{112}}
%e A323789 {{1}{2}} {{123}}
%e A323789 {{1}}{{2}} {{1}{11}}
%e A323789 {{1}{12}}
%e A323789 {{1}{23}}
%e A323789 {{2}{11}}
%e A323789 {{1}}{{11}}
%e A323789 {{1}}{{12}}
%e A323789 {{1}}{{23}}
%e A323789 {{1}{2}{3}}
%e A323789 {{2}}{{11}}
%e A323789 {{1}}{{1}{2}}
%e A323789 {{1}}{{2}{3}}
%e A323789 {{1}}{{2}}{{3}}
%Y A323789 Cf. A007716, A049311, A050343, A283877, A316980, A317791, A318564, A318565, A318566, A318812.
%Y A323789 Cf. A323787, A323788, A323790, A323791, A323792, A323793, A323794, A323795.
%K A323789 nonn,more
%O A323789 0,3
%A A323789 _Gus Wiseman_, Jan 27 2019