Numbers n such that uphi(sigma(n)) = n, where the uphi is the unitary phi function A047994.

Terms

a(0) =1a(1) =2a(2) =3a(3) =6a(4) =7a(5) =8a(6) =14a(7) =24a(8) =31a(9) =56a(10) =62a(11) =127a(12) =128a(13) =248a(14) =254a(15) =384a(16) =720a(17) =896a(18) =1016a(19) =3968a(20) =8191a(21) =16256a(22) =16382a(23) =32768a(24) =65528a(25) =98304a(26) =103680a(27) =131071a(28) =229376a(29) =262142