%I #4 Mar 30 2012 18:52:39
%S 1,2,4,6,38,66,398,1260,3980
%N 3*n-1 is a circular prime.
%Y Cf. A016114.
%K nonn,less
%O 1,2
%A _Juri-Stepan Gerasimov_, Feb 25 2010