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 A023326 Numbers n such that n remains prime through 4 iterations of the function f(x) = 9x + 8. 2

%I

%S 397,467,907,1747,1901,4099,7237,8117,8581,9371,9587,23539,28081,

%T 32611,36899,41729,54767,55207,57601,61991,64997,66449,73061,74821,

%U 75527,86291,115021,118717,125659,126067,134287,140677,147011,148147,151531,171539

%N Numbers n such that n remains prime through 4 iterations of the function f(x) = 9x + 8.

%C n, 9*n+8, 81*n+80, 729*n+728 and 6561*n+6560 are primes. - _Vincenzo Librandi_, Aug 04 2010

%H John Cerkan, <a href="/A023326/b023326.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Prime[Range[16000]],AllTrue[Rest[NestList[9#+8&,#,4]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jun 25 2017 *)

%o (MAGMA) [n: n in [1..5000000] | IsPrime(n) and IsPrime(9*n+8) and IsPrime(81*n+80) and IsPrime(729*n+728) and IsPrime(6561*n+6560)] // _Vincenzo Librandi_, Aug 04 2010

%Y Subsequence of A023235, A023267, and A023298.

%K nonn

%O 1,1

%A _David W. Wilson_

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Last modified August 19 04:10 EDT 2019. Contains 326109 sequences. (Running on oeis4.)