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%I #7 Jun 30 2018 13:54:05
%S 2,4,13,19,23,26,29,37,38,41,46,47,58,73,74,82,83,89,94,97,101,107,
%T 139,146,149,151,157,166,167,169,178,193,194,199,202,214,227,263,269,
%U 271,278,281,298,302,313,314,334,337,338,347,361,373,379,383,386,389
%N Numbers with primitive root 15.
%H Vincenzo Librandi, <a href="/A240096/b240096.txt">Table of n, a(n) for n = 1..1000</a>
%t pr = 15; Select[Range[2, 500], MultiplicativeOrder[pr, #] == EulerPhi[#] &]
%t Join[{2,4,13},Select[Range[2,400],PrimitiveRoot[#,15]==15&]] (* _Harvey P. Dale_, Jun 30 2018 *)
%Y Cf. numbers with positive primitive root r: A167791 (r=2), A167792 (r=3), A167793 (r=5), A167794 (r=6), A167795 (r=7), A167796 (r=8), A167797 (r=10), A240028 (r=11), A240030 (r=12), A240032 (r=13), A240094 (r=14).
%Y Cf. numbers with negative primitive root r: A167798 (r=-2), A167799 (r=-3), A167800 (r=-4), A167801 (r=-5), A167802 (r=-6), A167803 (r=-7), A167804 (r=-8), A167805 (r=-9), A167806 (r=-10), A240029 (r=-11), A240031 (r=-12), A240093 (r=-13), A240095 (r=-14), A240097 (r=-15).
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Apr 01 2014