Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #21 Aug 29 2018 03:27:52
%S 4111,7841,10111,15391,15991,16061,20011,21031,22699,32299,32957,
%T 35911,43963,45127,45631,47431,49831,51199,53173,53731,58111,59671,
%U 60331,64231,71761,74311,76039,78079,81331,81761,83311,83431,87541,98911,100621,102871,104729
%N Primes p whose smallest positive primitive root (mod p) is not squarefree.
%C A061325 is a proper subsequence.
%C A061330 is also a proper subsequence. - _Michel Marcus_, Feb 09 2016
%C Most of the terms have least primitive root 12. - _Jianing Song_, Aug 29 2018
%H Jianing Song, <a href="/A205581/b205581.txt">Table of n, a(n) for n = 1..1265</a>
%H Stephen D. Cohen, Tim Trudgian, <a href="http://arxiv.org/abs/1602.02440">On the least square-free primitive root modulo p</a>, arXiv:1602.02440 [math.NT], 2016.
%e 4111 is in the sequence since it is prime and its smallest primitive root (mod 4111) is 12.
%e 53173 is in the sequence since it is prime and its smallest primitive root (mod 53173) is 18.
%t Select[Prime[Range[10000]],!SquareFreeQ[PrimitiveRoot[#]]&] (* version 7.0 *)
%o (PARI) lista(nn) = forprime(p=2, nn, if (! issquarefree(lift(znprimroot(p))), print1(p, ", ")));
%Y Cf. A061325, A061330.
%K nonn
%O 1,1
%A _Emmanuel Vantieghem_, Jan 29 2012