login
This site is supported by donations to The OEIS Foundation.

 

Logo

Many excellent designs for a new banner were submitted. We will use the best of them in rotation.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A123692 Primes p such that p^2 divides 5^(p-1) - 1. 11
2, 20771, 40487, 53471161, 1645333507, 6692367337, 188748146801 (list; graph; refs; listen; history; text; internal format)
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.

C. K. Caldwell, The Prime Glossary, Fermat quotient.

F. G. Dorais and D. Klyve, A Wieferich prime search up to p < 6.7*10^15, J. Integer Seq. 14 (2011), Art. 11.9.2, 1-14.

PROG

(PARI)

N=10^9; default(primelimit, N);

forprime(n=2, N, if(Mod(5, n^2)^(n-1)==1, print1(n, ", ")));

\\ Joerg Arndt, May 01 2013

CROSSREFS

Cf. A001220, A014127, A123693, A128667, A128668, A090968, A128669, A096082.

Sequence in context: A124364 A173156 A214598 * A132942 A237521 A131558

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified April 24 09:00 EDT 2014. Contains 240957 sequences.