The book is now available! 7777777777
(another Prime Pages' Curiosity)
Prime Curios!
Curios: Curios Search:
 
Participate:
+ 7777777777 is the only ten-digit repdigit such that the product of itself and all truncations of itself minus two is prime. I.e., 7777777777*777777777*77777777*7777777*777777*77777*7777*777*77*7 - 2 is prime. [Patterson]

  To link to this page use http://primes.utm.edu/curios/page.php?number_id=3801



Prime Curios! © 1999-2009 (all rights reserved)