%I #7 May 23 2018 23:13:08
%S 1,2,7,56,1533,210302,496838435,309068803876372,
%T 14369391923126181310256825
%N Number of labeled clutters (connected antichains) spanning some subset of {1,...,n} with singleton edges allowed.
%F Binomial transform of A304985(n > 0).
%e The a(2) = 7 clutters:
%e {}
%e {{1}}
%e {{2}}
%e {{1,2}}
%e {{1},{1,2}}
%e {{2},{1,2}}
%e {{1},{2},{1,2}}
%Y Cf. A048143, A198085, A261006, A304912, A304981, A304982, A304983, A304984, A304985, A304986.
%K nonn
%O 0,2
%A _Gus Wiseman_, May 23 2018