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%I #8 May 23 2018 23:12:46
%S 1,1,2,5,19,176,16118,489996568
%N Number of unlabeled clutters (connected antichains) spanning up to n vertices without singleton edges.
%F Partial sums of A261006(n > 0).
%e Non-isomorphic representatives of the a(3) = 5 clutters:
%e {}
%e {{1,2}}
%e {{1,2,3}}
%e {{1,3},{2,3}}
%e {{1,2},{1,3},{2,3}}
%e Non-isomorphic representatives of the a(4) = 19 clutters:
%e {}
%e {{1,2}}
%e {{1,2,3}}
%e {{1,2,3,4}}
%e {{1,3},{2,3}}
%e {{1,4},{2,3,4}}
%e {{1,3,4},{2,3,4}}
%e {{1,2},{1,3},{2,3}}
%e {{1,2},{1,3,4},{2,3,4}}
%e {{1,3},{1,4},{2,3,4}}
%e {{1,3},{2,4},{3,4}}
%e {{1,4},{2,4},{3,4}}
%e {{1,2,4},{1,3,4},{2,3,4}}
%e {{1,2},{1,3},{1,4},{2,3,4}}
%e {{1,2},{1,3},{2,4},{3,4}}
%e {{1,4},{2,3},{2,4},{3,4}}
%e {{1,2,3},{1,2,4},{1,3,4},{2,3,4}}
%e {{1,3},{1,4},{2,3},{2,4},{3,4}}
%e {{1,2},{1,3},{1,4},{2,3},{2,4},{3,4}}
%Y Cf. A048143, A198085, A261006, A304912, A304981, A304982, A304983, A304984, A304985, A304986.
%K nonn
%O 0,3
%A _Gus Wiseman_, May 23 2018
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