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

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =9a(5) =14a(6) =20a(7) =27a(8) =83a(9) =119a(10) =164a(11) =219a(12) =285a(13) =363a(14) =454a(15) =1819a(16) =2379a(17) =3059a(18) =3875a(19) =4844a(20) =5984a(21) =7314a(22) =8854a(23) =10625a(24) =53129a(25) =65779a(26) =80729a(27) =98279a(28) =118754a(29) =142505