Perfect totient numbers.

Terms

a(0) =3a(1) =9a(2) =15a(3) =27a(4) =39a(5) =81a(6) =111a(7) =183a(8) =243a(9) =255a(10) =327a(11) =363a(12) =471a(13) =729a(14) =2187a(15) =2199a(16) =3063a(17) =4359a(18) =4375a(19) =5571a(20) =6561a(21) =8751a(22) =15723a(23) =19683a(24) =36759a(25) =46791a(26) =59049a(27) =65535a(28) =140103a(29) =177147