OFFSET
1,2
COMMENTS
As phi(2^(6*n+1)) = (2^n)^6, A277757 is a subsequence. - Bernard Schott, Sep 23 2022
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
phi of the sequence includes 1, 64, 4096, 46656,..; powers arise several times; a(3)= A053576(6) = 85; in sequence relatively large jumps are observable when power of new numbers appear.
MATHEMATICA
k=6; Select[Range[65000], IntegerQ[EulerPhi[#]^(1/k)]&] (* Harvey P. Dale, Feb 20 2011 *)
PROG
(PARI) is(n)=ispower(eulerphi(n), 6) \\ Charles R Greathouse IV, Apr 24 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 27 2002
STATUS
approved