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%I #21 Oct 09 2017 23:20:34
%S 0,1,1,2,3,5,6,9,12,17,22
%N Number of non-isomorphic finite multisets that cannot be expressed as the multiset-union of a set of sets.
%C Non-isomorphic finite multisets correspond to integer partitions. For example, the partition (3221) corresponds to the multiset {1,1,1,2,2,3,3,4}.
%C Problem: Is this sequence equal to A258939 or to A035948?
%e Representatives of the a(7) = 6 multisets are: {1,1,1,1,1,1,1}, {1,1,1,1,1,1,2}, {1,1,1,1,1,2,2}, {1,1,1,1,1,2,3}, {1,1,1,1,2,2,2}, {1,1,1,1,2,2,3}.
%Y Cf. A049311, A089259, A116540, A283877, A292432.
%K nonn,more
%O 1,4
%A _Gus Wiseman_, Oct 02 2017