%I
%S 0,1,7,17,19,25,27,43,47,55,57,59,61,71,77,79,91,93,97,101,107,109,
%T 117,127,133,143,145,147,149,151,159,161,163,167,169,177,185,195,197,
%U 199,203,205,207,223,227,235,241,257,259,263,267,271,275,277,289,291
%N Numbers m such that the number of distinct residues of the congruence x^m (mod 2m+1) equals 2m+1, x=0..2m.
%H Amiram Eldar, <a href="/A198032/b198032.txt">Table of n, a(n) for n = 0..10000</a>
%e a(2) = 7 because x^7 == 0, 1, ... 14 (mod 15) => 2*7+1 = 15 distinct residues.
%t lst:={};Table[If[Length[Union[PowerMod[Range[0,2*n],n,2*n+1]]]==2*n+1,AppendTo[lst,n]],{n,0,320}];lst
%Y Cf. A198020, A197930.
%K nonn
%O 0,3
%A _Michel Lagneau_, Oct 20 2011
