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%I #6 Oct 16 2019 13:10:36
%S 0,0,1,3,9,32,233,16578
%N Number of unlabeled, disconnected, nonempty antichains of subsets of {1..n}.
%C An antichain is a set of nonempty sets, none of which is a subset of any other. A singleton is considered to be connected.
%F a(n) = A327424(n) - 1.
%e Non-isomorphic representatives of the a(2) = 1 through a(4) = 9 antichains:
%e {{1},{2}} {{1},{2}} {{1},{2}}
%e {{1},{2,3}} {{1},{2,3}}
%e {{1},{2},{3}} {{1},{2},{3}}
%e {{1},{2,3,4}}
%e {{1,2},{3,4}}
%e {{1},{2},{3,4}}
%e {{1},{2},{3},{4}}
%e {{2},{1,3},{1,4}}
%e {{4},{1,2},{1,3},{2,3}}
%Y The labeled version is A327354 - 1.
%Y The covering case is A327426.
%Y Unlabeled antichains that are either not connected or not covering are A327437.
%Y The version with empty antichains allowed is A327424.
%Y Cf. A000372, A014466, A120338, A293606, A326704, A327062, A327355.
%K nonn,more
%O 0,4
%A _Gus Wiseman_, Sep 26 2019
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