A048010 - OEIS

A048010

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

%I #4 Mar 30 2012 18:56:54

%S 0,0,0,0,1,5,10,30,70,105,213,405,558,1110,2310,3300,7435,16575,23855,

%T 52871,113815,160615,346745,744345,1047438,2299998,5036862,7110522,

%U 15770601,34636245,48767082,107787262,236331302,331877557

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

%K nonn

%O 1,6

%A _Clark Kimberling_