%I #22 Sep 08 2022 08:44:47
%S 13,139,293,331,547,967,1049,1399,1567,1889,1997,2087,2137,2309,2423,
%T 2437,2753,2939,3719,3761,3919,4451,4517,4621,6089,7001,7741,8423,
%U 8849,9437,10487,11657,12007,12347,12823,13469,15289,15373,15661,17737,17989
%N Primes that remain prime through 3 iterations of function f(x) = 10x + 9.
%C Primes p such that 10*p+9, 100*p+99 and 1000*p+999 are also primes. - _Vincenzo Librandi_, Aug 04 2010
%H John Cerkan, <a href="/A023301/b023301.txt">Table of n, a(n) for n = 1..10000</a>
%t nrp3Q[n_]:=AllTrue[Rest[NestList[10#+9&,n,3]],PrimeQ]; Select[Prime[ Range[ 2100]],nrp3Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Aug 12 2019 *)
%o (Magma) [n: n in [1..450000] | IsPrime(n) and IsPrime(10*n+9) and IsPrime(100*n+99) and IsPrime(1000*n+999)] // _Vincenzo Librandi_, Aug 04 2010
%Y Subsequence of A023240, A023270, and A102700.
%K nonn
%O 1,1
%A _David W. Wilson_
|