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%I #30 Sep 08 2022 08:44:47
%S 421,773,1567,4111,68447,75721,111373,127301,137927,140321,156593,
%T 170767,177131,192341,194687,202637,240641,254407,254963,308303,
%U 321821,332951,395431,464131,515663,710081,822893,856393,989533,997123,1012201,1047077
%N Primes that remain prime through 5 iterations of the function f(x) = 9x + 4.
%C Primes p such that 9*p+4, 81*p+40, 729*p+364, 6561*p+3280 and 59049*p+29524 are also primes. - _Vincenzo Librandi_, Aug 05 2010
%H John Cerkan, <a href="/A023353/b023353.txt">Table of n, a(n) for n = 1..10000</a>
%t okQ[n_]:=And@@PrimeQ/@Rest[NestList[9#+4&,n,5]]; Select[Prime[Range[100000]],okQ] (* _Harvey P. Dale_, Jan 29 2011 *)
%o (Magma) [n: n in [1..19000000] | IsPrime(n) and IsPrime(9*n+4) and IsPrime(81*n+40) and IsPrime(729*n+364) and IsPrime(6561*n+3280) and IsPrime(59049*n+29524)] // _Vincenzo Librandi_, Aug 05 2010
%Y Subsequence of A023234, A023266, A023297, and A023325.
%K nonn
%O 1,1
%A _David W. Wilson_
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