%I #16 Mar 07 2015 15:34:08

%S 5107,20771,51427,52517,61417,66161,116731,119359,128657,140741,

%T 147647,150559,199783,203773,213949,229939,237283,261761,286751,

%U 288929,303089,339139,342373,381853,384611,385657,475897

%N Primes p for which exactly six bases b with 1 < b < p exist such that p is a base b Wieferich prime.

%C p = prime(n) such that A242830(n) = 6.

%H R. Fischer, <a href="http://www.fermatquotient.com/FermatQuotienten/ErstBasen.txt">Thema: Fermatquotient B^(P-1) == 1 (mod P^2) Fermatquotienten mit extremen Erst-Basen</a>

%o (PARI) forprime(p=1, , b=2; i=0; while(b < p, if(Mod(b, p^2)^(p-1)==1, i++); b++); if(i==6, print1(p, ", ")))

%Y Cf. A255203, A255204, A255205, A255206, A255207, A255208, A255210.

%K nonn,more

%O 1,1

%A _Felix Fröhlich_, Feb 17 2015