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Number of nonempty subsets of {1,2,...,n} in which exactly 4/5 of the elements are <= (n-3)/3.
0

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

%S 0,0,0,0,0,0,0,0,0,0,0,0,0,0,11,12,13,65,70,75,225,240,255,595,630,

%T 665,1501,1590,1680,4536,4851,5175,16215,17460,18750,57750,62205,

%U 66825,190035,204246,218979,590759,634075,679055,1836471

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

%K nonn

%O 1,15

%A _Clark Kimberling_