A167802 - OEIS

%I #7 Feb 23 2017 02:25:59

%S 13,17,19,23,41,47,61,67,71,89,109,113,137,157,167,169,211,229,233,

%T 257,263,277,283,289,331,359,361,373,383,397,401,449,479,503,521,523,

%U 529,547,569,593,599,613,619,641,647,661,691,709,719,733,739,743,757,761

%N Numbers with primitive root -6.

%H Vincenzo Librandi, <a href="/A167802/b167802.txt">Table of n, a(n) for n = 1..1000</a>

%t pr=-6; Select[Range[2,2000], MultiplicativeOrder[pr,# ] == EulerPhi[ # ] &]

%o (PARI) is(n)=gcd(n,6)==1 && znorder(Mod(-6,n))==eulerphi(n) && n>1 \\ _Charles R Greathouse IV_, Feb 23 2017

%Y Cf. A105878 (primes with primitive root -6)

%K nonn

%O 1,1

%A _T. D. Noe_, Nov 12 2009