%I
%S 3,107,421,773,1567,1637,3793,4111,6961,12721,14107,17851,26267,26557,
%T 31327,33503,37003,42281,57947,60091,65423,67427,68447,75721,82223,
%U 82657,87877,96377,108107,111373,113171,122117,123887,125497,125887,127301
%N Numbers n such that n remains prime through 4 iterations of function f(x) = 9x + 4.
%C n, 9*n+4, 81*n+40, 729*n+364 and 6561*n+3280 are primes.  _Vincenzo Librandi_, Aug 04 2010
%H John Cerkan, <a href="/A023325/b023325.txt">Table of n, a(n) for n = 1..10000</a>
%o (MAGMA) [n: n in [1..5000000]  IsPrime(n) and IsPrime(9*n+4) and IsPrime(81*n+40) and IsPrime(729*n+364) and IsPrime(6561*n+3280)] // _Vincenzo Librandi_, Aug 04 2010
%Y Subsequence of A023234, A023266, and A023297.
%K nonn
%O 1,1
%A _David W. Wilson_
