%I #4 Mar 30 2012 18:56:54
%S 0,0,0,0,2,8,20,41,63,126,252,505,1000,1936,3652,7305,14313,27573,
%T 52325,97868,180404,327692,586568,1034930,2718254,5012504,9131804,
%U 16440929,29259404,51482510,89575460,154146135,262403715,441956955
%N Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= sqrt(n).
%K nonn
%O 1,5
%A _Clark Kimberling_