This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A240028 #17 Mar 31 2014 18:39:07 %S A240028 2,3,4,6,9,13,17,18,23,26,27,29,31,34,41,46,47,54,58,59,62,67,71,73, %T A240028 81,82,94,101,103,109,118,134,142,146,149,162,163,169,173,179,197,202, %U A240028 206,218,223,233,243,251,277,281,289,293,298,326,331,338,346,358 %N A240028 Numbers with primitive root 11. %H A240028 Vincenzo Librandi, <a href="/A240028/b240028.txt">Table of n, a(n) for n = 1..1000</a> %t A240028 pr = 11; Select[Range[2, 400], MultiplicativeOrder[pr, #] == EulerPhi[#] &] %Y A240028 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). %Y A240028 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). %K A240028 nonn,easy %O A240028 1,1 %A A240028 _Vincenzo Librandi_, Mar 31 2014