Numbers n such that uphi(uphi(n)) = n/2.

Terms

a(0) =2a(1) =4a(2) =16a(3) =256a(4) =364a(5) =1456a(6) =3276a(7) =13104a(8) =21600a(9) =23296a(10) =65536a(11) =209664a(12) =249984a(13) =367200a(14) =1285632a(15) =3110400a(16) =5963776a(17) =6596304a(18) =9749376a(19) =23046144a(20) =27216000a(21) =33022080a(22) =52876800a(23) =53673984a(24) =76639680a(25) =94370400a(26) =105540864a(27) =119992320a(28) =245765520a(29) =285405120