Number of nonempty subsets of {1,2,...,n} in which exactly 5/6 of the elements are <= n/3.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =0a(10) =0a(11) =0a(12) =0a(13) =0a(14) =10a(15) =11a(16) =12a(17) =72a(18) =78a(19) =84a(20) =294a(21) =315a(22) =336a(23) =896a(24) =952a(25) =1008a(26) =2268a(27) =2394a(28) =2520a(29) =5230