login
Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= n/3.
0

%I #5 Mar 30 2012 18:56:53

%S 0,0,0,0,0,4,10,20,60,105,168,364,588,930,2250,3960,6820,17380,30745,

%T 52507,126763,219765,372120,898380,1572228,2702252,6619596,11666760,

%U 20167170,49146654,86461704,149465844,363087604,639438019

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

%K nonn

%O 1,6

%A _Clark Kimberling_