OFFSET
1,2
COMMENTS
Sequence is infinite, i.e., 3*2^(3*(t-1)-(-1)^t) is a term for all t > 0.
Prime terms (5, 110057537, ...) are in A246568 based on case A = +1.
PROG
(PARI) isok(n) = Mod(2, n^2)^eulerphi(n)==eulerphi(n)^2;
(Magma) [1] cat [n: n in [1..10^6] | 2^EulerPhi(n) mod n^2 eq EulerPhi(n)^2]; // Vincenzo Librandi, Sep 20 2018
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Altug Alkan, Sep 17 2018
STATUS
approved