A023269 - OEIS

%I #23 Sep 08 2022 08:44:47

%S 2,7,17,19,23,37,61,67,73,101,103,173,193,233,359,383,409,479,541,557,

%T 607,613,719,809,857,997,1013,1033,1109,1117,1237,1297,1361,1459,1531,

%U 1549,1699,1823,1871,1979,1999,2069,2131,2161,2347,2377,2399,2447,2663

%N Primes that remain prime through 2 iterations of function f(x) = 10x + 3.

%C Primes p such that 10*p+3 and 100*p+33 are also primes. - _Vincenzo Librandi_, Aug 04 2010

%H John Cerkan, <a href="/A023269/b023269.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Prime@ Range@ 400, Times @@ Boole@ PrimeQ@ Rest@ NestList[10 # + 3 &, #, 2] > 0 &] (* _Michael De Vlieger_, Sep 16 2016 *)

%t Select[Prime[Range[500]],AllTrue[Rest[NestList[10#+3&,#,2]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Sep 03 2018 *)

%o (Magma) [n: n in [1..100000] | IsPrime(n) and IsPrime(10*n+3) and IsPrime(100*n+33)] // _Vincenzo Librandi_, Aug 04 2010

%Y Subsequence of A023238 and of A102338.

%K nonn

%O 1,1

%A _David W. Wilson_