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A048021 Number of nonempty subsets of {1,2,...,n} in which exactly 1/5 of the elements are <= (n-2)/3. 0

%I

%S 0,0,0,0,1,5,15,30,70,141,213,405,765,1110,2310,4954,7435,16575,35945,

%T 52871,113815,240385,346745,744345,1595433,2299998,5036862,10959446,

%U 15770601,34636245,75326163,107787262,236331302,514828047

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

%K nonn

%O 1,6

%A _Clark Kimberling_

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Last modified January 19 04:18 EST 2021. Contains 340262 sequences. (Running on oeis4.)