1,1

Similarly to Wilson's theorem which states that (p-1)! == -1 mod p for every prime p, we can prove that (p-2)! == 1 mod p for every prime p. For the primes 2, 3, 11, 107, 4931 the above relations also holds mod p^2

Zhi-Wei SUN conjectures that all terms except 2 are == 3 mod 8 (Posting to the Number Theory Mailing List, Nov 02 2009; added by njas, Nov 02 2009)

Sequence in context: A117699 A065378 A161721 this_sequence A050721 A058114 A042337

Adjacent sequences: A079850 A079851 A079852 this_sequence A079854 A079855 A079856

nonn,more,new

Pavlos Saridis (pavlos19(AT)yahoo.com), Sep 13 2003