%I

%S 0,0,0,0,0,0,0,20,35,56,168,252,360,930,1452,2244,6820,11440,18655,

%T 52507,86905,139960,372120,617610,1007216,2702252,4563344,7573970,

%U 20167170,34220634,57059772,149465844,254222289,425926604

%N Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-2)/3.

%K nonn

%O 1,8

%A _Clark Kimberling_