Let S(n)=Sigma(n)/2. Numbers n such that S(S(n))=n, 1/2-Sociable number of order 1 or 2.

Terms

a(0) =6a(1) =12a(2) =14a(3) =28a(4) =48a(5) =62a(6) =112a(7) =124a(8) =160a(9) =189a(10) =192a(11) =254a(12) =448a(13) =496a(14) =508a(15) =1984a(16) =2032a(17) =8128a(18) =12288a(19) =16382a(20) =28672a(21) =32764a(22) =126976a(23) =131056a(24) =196608a(25) =262142a(26) =458752a(27) =520192a(28) =524224a(29) =524284