OFFSET
1,1
COMMENTS
All terms are even, as 2^phi(m) == 1 (mod m) if m is odd. - Robert Israel, Sep 02 2018
Perfect power terms are 144, 576, 900, 1600, 3136, 9216, 12544, 20736, 36864, 57600, 63504, ... - Altug Alkan, Sep 04 2018
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
ispow:= proc(n) local F;
F:= map(t -> t[2], ifactors(n)[2]);
igcd(op(F)) > 1
end proc:
select(m -> ispow(2 &^ numtheory:-phi(m) mod m), [seq(i, i=2..1000, 2)]); # Robert Israel, Sep 02 2018
MATHEMATICA
okQ[n_] := GCD @@ FactorInteger[PowerMod[2, EulerPhi[n], n]][[All, 2]] > 1;
Select[Range[2, 1000, 2], okQ] (* Jean-François Alcover, Aug 02 2019 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Sep 01 2018
EXTENSIONS
Definition corrected by Robert Israel, Sep 02 2018
STATUS
approved