A304983 - OEIS

%I #10 Aug 14 2019 19:19:55

%S 1,1,3,14,118,2916,819473

%N Number of unlabeled clutters (connected antichains) spanning n vertices with singleton edges allowed.

%F Inverse Euler transform of A304997. - _Andrew Howroyd_, Aug 14 2019

%e Non-isomorphic representatives of the a(3) = 14 clutters:

%e   {{1,2,3}}

%e   {{1,3},{2,3}}

%e   {{3},{1,2,3}}

%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, A304997.

%K nonn,more

%O 0,3

%A _Gus Wiseman_, May 23 2018

%E a(5)-a(6) from _Andrew Howroyd_, Aug 14 2019