%N a(n) gives least prime for which the n-th prime is the least prime which is not a primitive root of a(n) (see A060084), or 0 if the n-th prime never occurs in A060084.
%C Note that these are the smallest primes such that exactly the first n primes are primitive roots.
%C a(n) gives the prime corresponding to the first appearance of the n-th prime in A060084. The n-th prime is the least prime not a primitive root of a(n) and for all primes p < a(n) the n-th prime (i.e. A000040(n)) is either a primitive root of p, or else there is a smaller prime q which is not a primitive root of a(n). Question: does a value exist for all primes?
%H Don Reble, <a href="/A060085/b060085.txt">Table of n, a(n) for n = 1..40</a>
%e a(4)=23 because the first occurrence of 7 in A060084 is at n=9 and the 9th prime, A000040(9)=23. That is, a(4)=23 since the 4th prime, A000040(4), is 7 and 23 is the smallest prime p for which 7 is the least prime that is not a primitive root of p.
%Y Cf. A000040, A060084.
%A _Marc LeBrun_, Feb 23 2001
%E Corrected by _Jud McCranie_, Sep 03 2002