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Old 2007-07-27, 03:09   #3
wblipp's Avatar
May 2003
New Haven

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Originally Posted by Googol View Post
It just seemed to me that this passage in the book is implying that there is no such pattern using base 10
The base 10 pattern has 8 possible endings, corresponding to the fact that after the first few, all primes are 20k+1, 20k+3, 20k+7, 20k+9, 20k+11, 20k+13, 20k+17, or 20k+19. The sequence 2^n mod 100 repeats in a cycle of length 20. The possible endings are 51, 07, 27, 11, 47, 91, 71, and 87 respectively.

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