Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= (n-4)/2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =7a(10) =8a(11) =32a(12) =36a(13) =90a(14) =100a(15) =245a(16) =275a(17) =770a(18) =882a(19) =2520a(20) =2912a(21) =7930a(22) =9184a(23) =24430a(24) =28400a(25) =76010a(26) =88880a(27) =239420a(28) =281384a(29) =755378