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 A323791 #5 Jan 28 2019 08:07:19
%S A323791 1,1,4,13,52,196,877,3917
%N A323791 Number of non-isomorphic weight-n sets of multisets of sets.
%C A323791 All sets and multisets must be finite, and only the outermost may be empty.
%C A323791 The weight of an atom is 1, and the weight of a multiset is the sum of weights of its elements, counting multiplicity.
%e A323791 Non-isomorphic representatives of the a(1) = 1 through a(3) = 13 sets of multisets of sets:
%e A323791 {{1}} {{12}} {{123}}
%e A323791 {{1}{1}} {{1}{12}}
%e A323791 {{1}{2}} {{1}{23}}
%e A323791 {{1}}{{2}} {{1}{1}{1}}
%e A323791 {{1}}{{12}}
%e A323791 {{1}{1}{2}}
%e A323791 {{1}}{{23}}
%e A323791 {{1}{2}{3}}
%e A323791 {{1}}{{1}{1}}
%e A323791 {{1}}{{1}{2}}
%e A323791 {{1}}{{2}{3}}
%e A323791 {{2}}{{1}{1}}
%e A323791 {{1}}{{2}}{{3}}
%Y A323791 Cf. A007716, A049311, A050326, A050343, A283877, A306186, A316980, A318564, A318565, A318566, A318812.
%Y A323791 Cf. A323787, A323788, A323789, A323790, A323792, A323793, A323794, A323795.
%K A323791 nonn,more
%O A323791 0,3
%A A323791 _Gus Wiseman_, Jan 27 2019