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%I #21 Sep 08 2022 08:44:47
%S 3,7,11,17,23,31,37,41,67,71,73,83,97,107,113,137,163,191,193,197,223,
%T 263,283,307,311,317,337,353,367,373,401,421,461,491,577,601,613,617,
%U 631,643,647,653,661,683,727,743,751,773,797,821,823,853,857,881,883,907,947
%N Primes p such that 9*p + 4 is also prime.
%H Vincenzo Librandi, <a href="/A023234/b023234.txt">Table of n, a(n) for n = 1..2000</a>
%t Select[Prime[Range[1000]], PrimeQ[9 # + 4]&] (* _Vincenzo Librandi_, Feb 02 2014 *)
%o (Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(9*n+4)]; // _Vincenzo Librandi_, Nov 20 2010
%K nonn,easy
%O 1,1
%A _David W. Wilson_
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