%I A023270
%S A023270 5,13,19,23,47,61,103,127,139,233,257,293,331,433,463,491,499,547,593,
%T A023270 701,859,967,1009,1013,1049,1223,1321,1399,1493,1567,1723,1811,1867,1889,
%U A023270 1997,2039,2063,2087,2137,2203,2267,2273,2309,2423,2437,2441,2609,2633
%N A023270 Numbers n such that n remains prime through 2 iterations of function 
               f(x) = 10x + 9.
%Y A023270 Sequence in context: A162174 A118915 A084442 this_sequence A103804 A129919 
               A045454
%Y A023270 Adjacent sequences: A023267 A023268 A023269 this_sequence A023271 A023272 
               A023273
%K A023270 nonn
%O A023270 1,1
%A A023270 David W. Wilson (davidwwilson(AT)comcast.net)