286689

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 2/5 of the elements are <= (n-4)/2.at n=21A048066
• a(n) = Sum_{k=0..floor(n/3)} |Stirling1(n - 2*k,n - 3*k)|.at n=19A357931