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

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =5a(6) =6a(7) =7a(8) =35a(9) =44a(10) =54a(11) =219a(12) =285a(13) =363a(14) =1364a(15) =1819a(16) =2379a(17) =8567a(18) =11627a(19) =15503a(20) =54263a(21) =74612a(22) =100946a(23) =346103a(24) =480699a(25) =657799a(26) =2220074a(27) =3108104a(28) =4292144a(29) =14307149