Perfex numbers: n = binary XOR of divisors of n.

Terms

a(0) =1a(1) =6a(2) =120a(3) =198a(4) =3696a(5) =6240a(6) =32640a(7) =56160a(8) =1941408a(9) =3592200a(10) =8119800a(11) =15628032a(12) =27125280a(13) =59032080a(14) =61788240a(15) =125859840a(16) =1635834720a(17) =2147450880a(18) =3709081680a(19) =16328199552a(20) =26198072160a(21) =52344970080a(22) =52396088160a(23) =209584184160a(24) =210197601120a(25) =236223190200a(26) =237385437360