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Primes p such that 9*p + 2 is also prime.
4

%I #26 Sep 08 2022 08:44:47

%S 3,5,11,19,29,31,43,53,71,73,101,103,109,113,131,151,173,179,191,211,

%T 229,233,239,269,271,281,283,311,313,373,379,383,431,443,491,499,509,

%U 521,541,599,613,619,653,691,701,719,733,739,743,751,773,809,883,919,929,971,983

%N Primes p such that 9*p + 2 is also prime.

%H John Cerkan, <a href="/A023233/b023233.txt">Table of n, a(n) for n = 1..10000</a>

%p A023233:=n->`if`(isprime(n) and isprime(9*n+2), n, NULL): seq(A023233(n), n=1..10^3); # _Wesley Ivan Hurt_, Sep 08 2016

%t Select[Prime[Range[200]], PrimeQ[9#+2]&] (* _Harvey P. Dale_, Dec 02 2010 *)

%o (Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(9*n+2)] // _Vincenzo Librandi_, Nov 20 2010

%K nonn

%O 1,1

%A _David W. Wilson_