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 A255207 Primes p for which exactly four bases b with 1 < b < p exist such that p is a base b Wieferich prime. 8
 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 (list; graph; refs; listen; history; text; internal format)
 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

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Last modified April 23 01:11 EDT 2024. Contains 371906 sequences. (Running on oeis4.)