OFFSET
1,3
PROG
(PARI) forstep(p=3, 10^15, 2, if(!Mod(p, 5)==0, if(isprime(p), o=znorder(Mod(5, p)); x=ispower(2*o); if(2^(x-1)==o, print1(x-2, ", ")))));
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Arkadiusz Wesolowski, Jun 25 2016
STATUS
approved