|
%I #9 Feb 23 2019 21:33:40
%S 0,0,1,3,12,48,217,1005,4878,24218,123021,634995,3323963,17596131,
%T 94053675,506865965,2751093957,15025119759,82511460766,455331632088,
%U 2523688452540,14042621802676,78415665739800,439298161502112,2468288819015277
%N The sequence S defined in A058540.
%p spec := [ S, {N=Union(Z,S,P,Q), S=Set(Union(Z,P,Q),card>=2), P=Set(Union(Z,S,Q),card>=2), Q=Set(Union(Z,S,P),card>=2)} ]; [seq(combstruct[count](spec,size=n), n=0..40)]; # N=A058540, S=A058371
%p spec:=[S,{S=Set(Union(Z,S,S),card>=2)}];[seq(combstruct[count](spec,size=n),n=0..25)]; # _Vladeta Jovovic_, Jun 25 2007
%Y Cf. A058575.
%K nonn
%O 0,4
%A _N. J. A. Sloane_, Dec 26 2000
|
