OFFSET
1,2
COMMENTS
MATHEMATICA
Select[Range[1000], PowerMod[2, #, #] == PowerMod[2, (e = EulerPhi[#]), e] &] (* Amiram Eldar, Feb 11 2021 *)
PROG
(PARI) f(n) = lift(Mod(2, n)^n); \\ A015910
isok(k) = f(k) == f(eulerphi(k)); \\ Michel Marcus, Feb 11 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 03 2002
STATUS
approved