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%I #12 Aug 14 2019 19:21:09
%S 1,2,5,19,137,3053,822526
%N Number of unlabeled clutters (connected antichains) spanning up to n vertices with singleton edges allowed.
%C The initial terms 1, 2, 5, 19 are the same as A304981 but the remaining terms differ.
%F Partial sums of A304983.
%e Non-isomorphic representatives of the a(3) = 19 clutters:
%e {}
%e {{1}}
%e {{1,2}}
%e {{1,2,3}}
%e {{2},{1,2}}
%e {{1,3},{2,3}}
%e {{3},{1,2,3}}
%e {{1},{2},{1,2}}
%e {{1,2},{1,3},{2,3}}
%e {{3},{1,2},{2,3}}
%e {{3},{1,3},{2,3}}
%e {{2},{3},{1,2,3}}
%e {{1},{2},{3},{1,2,3}}
%e {{2},{3},{1,2},{1,3}}
%e {{3},{1,2},{1,3},{2,3}}
%e {{2},{3},{1,3},{2,3}}
%e {{1},{2},{3},{1,3},{2,3}}
%e {{2},{3},{1,2},{1,3},{2,3}}
%e {{1},{2},{3},{1,2},{1,3},{2,3}}
%Y Cf. A048143, A198085, A261006, A304912, A304981, A304982, A304983, A304984, A304985, A304986.
%K nonn,more
%O 0,2
%A _Gus Wiseman_, May 23 2018
%E a(5)-a(6) from _Andrew Howroyd_, Aug 14 2019
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