A211076 - OEIS

%I #7 May 13 2013 01:54:21

%S 3,7,11,17,23,31,41,31,31,53,47,53,47,59,67,89,79,83,97,101,101,101,

%T 139,113,167,127,107,151,137,149,197,157,151,149,167,239,223,229,191,

%U 211,211,239,211,277,239,251,241,313,257,251,313,307,307,347,347,347

%N Least prime q such that k^p - p is not divisible by q for any positive integer k, where p is the n-th prime.

%C For p > 2 there is some prime dividing sigma(p^(p-1)) for which k^p - p is not divisible by the prime for any k. Thus a(n) exists and is at most sigma(p^(p-1)).

%H Charles R Greathouse IV, <a href="/A211076/b211076.txt">Table of n, a(n) for n = 1..1000</a>

%o (PARI) a(n)=my(p=prime(n)); forprime(q=2,default(primelimit),for(k=2,p, if(Mod(k,q)^p==p,next(2))); return(q)) \\ _Charles R Greathouse IV_, May 09 2012

%K nonn

%O 1,1

%A _Charles R Greathouse IV_, May 09 2012