

A123692


Primes p such that p^2 divides 5^(p1)  1.


19




OFFSET

1,1


COMMENTS

Dorais and Klyve proved that there are no further terms up to 9.7*10^14.


LINKS

Table of n, a(n) for n=1..7.
Chris K. Caldwell, The Prime Glossary, Fermat quotient.
François G. Dorais and Dominic Klyve, A Wieferich prime search up to p < 6.7*10^15, J. Integer Seq. 14 (2011), Art. 11.9.2, 114.
A. Paszkiewicz, A new prime p for which the least primitive root (mod p) and the least primitive root (mod p^2) are not equal, Math. Comp. 78 (2009), 11931195.


MATHEMATICA

Select[Prime[Range[2500]], Divisible[5^(#  1)  1, #^2] &] (* Alonso del Arte, Aug 01 2014 *)


PROG

(PARI)
N=10^9; default(primelimit, N);
forprime(n=2, N, if(Mod(5, n^2)^(n1)==1, print1(n, ", ")));
\\ Joerg Arndt, May 01 2013


CROSSREFS

Cf. A001220, A014127, A123693, A128667, A128668, A090968, A128669, A096082.
Sequence in context: A173156 A214598 A242959 * A261362 A132942 A237521
Adjacent sequences: A123689 A123690 A123691 * A123693 A123694 A123695


KEYWORD

hard,nonn,more


AUTHOR

Max Alekseyev, Oct 07 2006


EXTENSIONS

More terms from Alexander Adamchuk, Nov 27 2006
Updated by Max Alekseyev, Jan 29 2012


STATUS

approved



