A048045 - OEIS

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A048045

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

%I #5 Mar 30 2012 18:56:54

%S 0,0,0,0,0,0,0,10,15,21,84,112,144,360,450,550,1430,1815,2275,7735,

%T 10192,13230,44100,57680,74256,223720,288456,367080,1105800,1427850,

%U 1824690,5784240,7521360,9684840,30936334,40225735,51798175

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

%Y Shares a bisection with A047200.

%K nonn

%O 1,8

%A _Clark Kimberling_