OFFSET
1,2
EXAMPLE
phi(101) = 10^2, and phi(102) = 2^5.
phi(3458) = 6^4, and phi(3459) = 48^2.
MATHEMATICA
perfectPowerQ[1] = True; perfectPowerQ[n_] := GCD @@ FactorInteger[n][[;; , 2]] > 1; Select[Range[30000], And @@ perfectPowerQ /@ EulerPhi[# + {0, 1}] &] (* Amiram Eldar, Feb 04 2020 *)
PROG
(PARI) v=[1]; for(i = 2, 30000, if(ispower(eulerphi(i)), if(ispower(eulerphi(i+1)), v = concat(v, i)))); v
(Magma) [1] cat [k:k in [3..30000]|IsPower(EulerPhi(k)) and IsPower(EulerPhi(k+1))]; // Marius A. Burtea, Feb 05 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Antonio Roldán, Feb 04 2020
STATUS
approved