A048067 - OEIS

A048067

Number of nonempty subsets of {1,2,...,n} in which exactly 3/5 of the elements are <= (n-4)/2.

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

%S 0,0,0,0,0,0,0,0,0,21,28,112,144,360,450,1110,1430,4235,5775,17556,

%T 24388,68328,94731,251160,349300,923230,1301080,3482710,4976070,

%U 13287846,19136832,50391978,72898098

%N Number of nonempty subsets of {1,2,...,n} in which exactly 3/5 of the elements are <= (n-4)/2.

%K nonn

%O 1,10

%A _Clark Kimberling_