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 A144561 Prime p such that p^2+13p+23 is prime. 2

%I

%S 2,3,5,7,19,37,41,47,59,71,73,103,157,163,211,227,229,239,283,293,311,

%T 313,337,353,359,367,419,443,463,499,521,523,577,619,643,647,653,661,

%U 733,751,787,839,853,863,877,883,929,1021,1069,1087,1123,1129,1163

%N Prime p such that p^2+13p+23 is prime.

%H Vincenzo Librandi, <a href="/A144561/b144561.txt">Table of n, a(n) for n = 1..1000</a>

%p a := proc (n) if isprime(n) = true and isprime(n^2+13*n+23) = true then n else end if end proc: seq(a(n), n = 2 .. 1300); # _Emeric Deutsch_, Jan 20 2009

%t Select[Prime[Range[200]], PrimeQ[#^2 + 13 # + 23] &] (* _Vincenzo Librandi_, Aug 30 2012 *)

%o (MAGMA) [p: p in PrimesUpTo(1500) | IsPrime(p^2+13*p+23)] // _Vincenzo Librandi_, Aug 30 2012

%o (PARI) isok(p) = isprime(p) && isprime(p^2+13*p+23); \\ _Michel Marcus_, Feb 10 2018

%Y Cf. A153781.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Jan 03 2009

%E Extended by _Emeric Deutsch_, Jan 20 2009

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Last modified August 6 17:06 EDT 2020. Contains 336255 sequences. (Running on oeis4.)