OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..500
EXAMPLE
phi(41) + 41 = 81 = 3^4.
MATHEMATICA
Select[Range[140000], IntegerQ[Surd[#+EulerPhi[#], 4]]&] (* Harvey P. Dale, Sep 27 2020 *)
PROG
(PARI) isok(n) = ispower(eulerphi(n) + n, 4); \\ Michel Marcus, Jan 09 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Giovanni Resta, Feb 13 2006
STATUS
approved