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%I #5 Oct 21 2017 21:08:16
%S 1,1,3,6,16,35,98,242,690
%N Number of unlabeled multiset antichains of weight n.
%C A multiset antichain is a finite set of finite nonempty multisets, none of which is a submultiset of any other. The weight of an antichain is the sum of cardinalities (counting multiplicity) of its elements.
%F Euler transform of A293994.
%e Non-isomorphic representatives of the a(4) = 16 antichains are:
%e ((1111)), ((1112)), ((1122)), ((1123)), ((1234)),
%e ((1)(234)), ((2)(111)), ((2)(113)), ((11)(12)), ((11)(22)), ((11)(23)), ((12)(13)), ((12)(34)),
%e ((1)(2)(34)),((2)(3)(11)),
%e ((1)(2)(3)(4)).
%Y Cf. A007716, A285572, A293606, A293994.
%K nonn,more
%O 0,3
%A _Gus Wiseman_, Oct 21 2017