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Least number m such that 3^m == +- 1 (mod 3n + 1).
0

%I #11 Oct 22 2023 16:58:10

%S 1,3,2,3,4,9,5,10,3,15,8,9,4,21,11,21,6,20,14,5,16,11,12,6,9,39,4,16,

%T 10,6,23,24,20,17,26,27,12,44,29,5,15,63,12,9,16,69,35,14,9,25,30,39,

%U 8,81,41,39,21,60,44,45,22,80,36,8,21,99,50,8,12,105,53

%N Least number m such that 3^m == +- 1 (mod 3n + 1).

%t Table[Module[{m=1},While[PowerMod[3,m,3n+1]!=1&&PowerMod[3,m,3n+1] != 3n, m++];m],{n,60}] (* _Harvey P. Dale_, Jul 29 2018 *)

%K nonn

%O 1,2

%A _N. J. A. Sloane_