Number of nonempty subsets of {1,2,...,n} in which exactly 5/6 of the elements are <= (n+3)/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) =7a(12) =8a(13) =9a(14) =54a(15) =60a(16) =66a(17) =231a(18) =252a(19) =273a(20) =728a(21) =784a(22) =840a(23) =1890a(24) =2016a(25) =2142a(26) =4420a(27) =4689a(28) =4959a(29) =10659