A244546 - OEIS

%I #16 Jul 17 2014 21:23:59

%S 997,1879,2617,85091

%N Wieferich primes p to base p-th prime.

%C No further terms up to 10^6.

%C No further terms up to 10^11. - _Luke March_, Jul 16 2014

%e a(1) = 997, since prime(997) = 7883 and 7883^996 % 997^2 = 1.

%o (PARI) forprime(p=2, 10^6, q=prime(p); if(Mod(q, p^2)^(p-1)==1, print1(p, ", ")))

%Y Cf. A001220, A174422, A178900, A196202.

%K nonn,hard,more

%O 1,1

%A _Felix Fröhlich_, Jun 29 2014