A048012 - OEIS

A048012

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

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

%S 0,0,0,0,0,0,0,0,0,21,28,36,144,180,220,550,660,780,2275,2821,3465,

%T 13230,16940,21420,74256,94248,118104,367080,461700,574644,1824690,

%U 2310000,2899380,9684840,12357532,15634300,51798175,66098175

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

%K nonn

%O 1,10

%A _Clark Kimberling_