Primes p such that cototient(totient(p)) = A070556(p) is a power of 2.

Terms

a(0) =3a(1) =5a(2) =7a(3) =13a(4) =17a(5) =29a(6) =97a(7) =113a(8) =193a(9) =257a(10) =449a(11) =509a(12) =769a(13) =7937a(14) =12289a(15) =65537a(16) =114689a(17) =520193a(18) =786433a(19) =7340033a(20) =8388593a(21) =33292289a(22) =33550337a(23) =469762049a(24) =2130706433a(25) =3221225473a(26) =8588886017a(27) =137438691329a(28) =206158430209