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 A320797 #7 Nov 05 2018 21:01:08
%S A320797 1,0,1,1,3,4,9,15,33,60,121
%N A320797 Number of non-isomorphic self-dual multiset partitions of weight n with no singletons.
%C A320797 Also the number of nonnegative integer square symmetric matrices with sum of elements equal to n and no rows or columns summing to 0 or 1, up to row and column permutations.
%e A320797 Non-isomorphic representatives of the a(2) = 1 through a(7) = 15 multiset partitions:
%e A320797 {{11}} {{111}} {{1111}} {{11111}} {{111111}} {{1111111}}
%e A320797 {{11}{22}} {{11}{122}} {{111}{222}} {{111}{1222}}
%e A320797 {{12}{12}} {{11}{222}} {{112}{122}} {{111}{2222}}
%e A320797 {{12}{122}} {{11}{2222}} {{112}{1222}}
%e A320797 {{12}{1222}} {{11}{22222}}
%e A320797 {{22}{1122}} {{12}{12222}}
%e A320797 {{11}{22}{33}} {{122}{1122}}
%e A320797 {{11}{23}{23}} {{22}{11222}}
%e A320797 {{12}{13}{23}} {{11}{12}{233}}
%e A320797 {{11}{22}{233}}
%e A320797 {{11}{22}{333}}
%e A320797 {{11}{23}{233}}
%e A320797 {{12}{12}{333}}
%e A320797 {{12}{13}{233}}
%e A320797 {{13}{23}{123}}
%e A320797 Inequivalent representatives of the a(6) = 9 symmetric matrices with no rows or columns summing to 1:
%e A320797 [6]
%e A320797 .
%e A320797 [3 0] [2 1] [4 0] [3 1] [2 2]
%e A320797 [0 3] [1 2] [0 2] [1 1] [2 0]
%e A320797 .
%e A320797 [2 0 0] [2 0 0] [1 1 0]
%e A320797 [0 2 0] [0 1 1] [1 0 1]
%e A320797 [0 0 2] [0 1 1] [0 1 1]
%Y A320797 Cf. A000219, A007716, A302545, A316980, A316983, A319560, A319616, A319721.
%Y A320797 Cf. A320796, A320798, A320799, A320804, A320811, A320812, A320813.
%K A320797 nonn,more
%O A320797 0,5
%A A320797 _Gus Wiseman_, Nov 02 2018