OFFSET
1,1
COMMENTS
For p = 5 and 113 is 68^(p-1) == 1 (mod p^3).
No further terms up to 7.74*10^13 (cf. Fischer link). - Felix Fröhlich, Dec 27 2016
LINKS
MATHEMATICA
Select[Prime[Range[500]], PowerMod[68, #-1, #^2]==1&] (* Harvey P. Dale, Aug 07 2019 *)
PROG
(PARI) forprime(p=1, , if(Mod(68, p^2)^(p-1)==1, print1(p, ", "))) \\ Felix Fröhlich, Dec 27 2016
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Thomas Ordowski, Dec 27 2016
EXTENSIONS
a(5) from Felix Fröhlich, Dec 27 2016
STATUS
approved