A048029 - OEIS

A048029

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

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

%S 0,0,0,0,0,0,0,0,7,8,9,27,30,33,121,138,156,520,595,675,2255,2600,

%T 2975,9877,11445,13167,43510,50625,58513,192801,225093,261165,858199,

%U 1004754,1169505,3834655,4500210,5252445,17189667,20214327

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

%K nonn

%O 1,9

%A _Clark Kimberling_