A211875 Primes of the form Phi(phi(k),3), the phi(k)-th Cyclotomic polynomial evaluated at 3, where phi is the Euler totient function.

2, 7, 61, 73, 6481, 530713, 42521761, 47763361, 23535794707, 282429005041, 374857981681, 150094634909578633, 13490012358249728401, 105919308797935444986721, 1076050302914923449767311155851656076154481

Offset: 1

Author

Alexander Gruber, Feb 12 2013

Keywords

• nonn

Programs

Mathematica

Union[Select[Cyclotomic[EulerPhi[#], x] /. x -> 3 & /@ Range[1000], PrimeQ]]