Number of subsets of {1..n} containing n whose mean is not an element.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =6a(5) =12a(6) =26a(7) =54a(8) =112a(9) =226a(10) =460a(11) =930a(12) =1876a(13) =3780a(14) =7606a(15) =15288a(16) =30720a(17) =61680a(18) =123786a(19) =248346a(20) =498072a(21) =998636a(22) =2001826a(23) =4011942a(24) =8039072a(25) =16106124a(26) =32263876a(27) =64623330a(28) =129424236a(29) =259179060