OFFSET
1,1
COMMENTS
a(17) > 10^9.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..95 (terms < 10^14)
MATHEMATICA
Select[Range[65*10^7], PowerMod[6, EulerPhi[#], #^2]==1&] (* Harvey P. Dale, Jan 20 2020 *)
PROG
(PARI) for(n=2, 1e9, if(Mod(6, n^2)^(eulerphi(n))==1, print1(n, ", ")))
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Aug 10 2014
EXTENSIONS
Terms a(17) and beyond from Giovanni Resta, Jan 24 2020
STATUS
approved