A167795 - OEIS

%I #7 Jan 04 2025 00:35:21

%S 2,4,5,10,11,13,17,22,23,26,34,41,46,61,67,71,79,82,89,97,101,107,121,

%T 122,127,134,142,151,158,163,169,173,178,179,194,202,211,214,229,239,

%U 241,242,254,257,263,269,289,293,302,326,338,346,347,349,358,359,379

%N Numbers with primitive root 7.

%H Vincenzo Librandi, <a href="/A167795/b167795.txt">Table of n, a(n) for n = 1..1000</a>

%t pr=7; Select[Range[2,2000], MultiplicativeOrder[pr,# ] == EulerPhi[ # ] &]

%o (PARI) is(n)=if(n%7==0, return(0)); my(p=eulerphi(n)); znorder(Mod(7, n), p)==p \\ _Charles R Greathouse IV_, Jan 04 2025

%Y Cf. A019337 (primes with primitive root 7)

%K nonn

%O 1,1

%A _T. D. Noe_, Nov 12 2009