OFFSET
1,1
COMMENTS
a(8) > 10^13 if it exists. - Jason Yuen, May 12 2024
Equivalently, primes p such that 7^p == p+7 (mod p^2), or Fermat quotient q_p(7) == 1/7 (mod p). - Max Alekseyev, Sep 16 2024
PROG
(PARI) forprime(p=1, , if(Mod(p+7, p^2)^(p-1)==1, print1(p, ", ")))
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Felix Fröhlich, Jul 21 2022
EXTENSIONS
a(7) from Jason Yuen, May 12 2024
STATUS
approved