%I #19 Jun 29 2024 16:44:03
%S 1,175952,348880,649078,951625,1495472,1944320,3140852,3483200,
%T 3643270,4359040,4703776,6513584,8170904,9854200,11005568,11831890,
%U 12149872,12828200,12910928,18095630,18964400,22034516,43599424,62849024,66322480,82159588,85181600
%N Numbers k such that 3k - 1 divides 3^k - 1 and 3 does not divide k.
%t Select[Range[10^6], Mod[#,3] > 0 && PowerMod[3, #, 3*#-1] == 1 &] (* _Giovanni Resta_, May 29 2016 *)
%o (PARI) is(n)=n%3 && Mod(3,3*n-1)^n==1 \\ _Charles R Greathouse IV_, May 29 2016
%Y Cf. A233415. Subsequence of A273614.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, May 28 2016