This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A111027 Wieferich primes in base 12. 2

%I

%S 2693,123653

%N Wieferich primes in base 12.

%C I have searched up to the 9 millionth prime, 160481183 and gave up trying to find a third term. The sequence is conjectured to be infinite. If the behavior is similar to base 10, A045616, then the next term could be greater than 2*10^11. In base 12 with X for ten and E for eleven the sequence is [1685, 5E685] so it would be interesting to see if the third term ends in 685 as well. These primes are also the Wieferich numbers in base 12: 12^phi(n) = 1 mod n^2.

%F 12^(p-1) = 1 mod p^2

%p WP:=[]: for z from 1 to 1 do for k from 1 to 9000000 do p:=ithprime(k); if 12 &^(p-1) mod p^2 = 1 then WP:=[op(WP),p]; printf("p=%d, ",p); fi; if k mod 10^5 = 0 then printf("k=%d, ",k); fi; od; od; WP;

%Y Cf. A001220, A039951, A045616, A077815, A077816.

%K nonn,bref

%O 1,1

%A _Walter Kehowski_, Oct 05 2005

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

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

Last modified May 18 07:10 EDT 2013. Contains 225419 sequences.