A255207 Primes p for which exactly four bases b with 1 < b < p exist such that p is a base b Wieferich prime.

487, 1163, 2203, 2731, 3373, 4391, 5261, 6343, 6451, 6569, 7753, 8377, 8863, 9041, 9397, 9463, 9941, 10079, 10321, 11783, 12703, 13121, 13151, 13807, 13903, 14419, 15061, 15263, 15313, 15601, 16631, 16883, 16943, 17477, 17519, 18253, 18773, 20173, 22279, 23291

Offset

1,1

Comments

p = prime(n) such that A242830(n) = 4.

Links

Table of n, a(n) for n=1..40.

Prog

(PARI) forprime(p=1, , b=2; i=0; while(b < p, if(Mod(b, p^2)^(p-1)==1, i++); b++); if(i==4, print1(p, ", ")))

Crossrefs

Cf. A255203, A255204, A255205, A255206, A255208, A255209, A255210.

Sequence in context: A142540 A048424 A142858 * A236424 A235839 A203873

Adjacent sequences: A255204 A255205 A255206 * A255208 A255209 A255210

Keyword

nonn

Author

Felix Fröhlich, Feb 17 2015

Status

approved