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%I #7 Sep 08 2022 08:45:51
%S 5,7,11,17,31,61,79,101,137,163,193,227,311,401,509,521,641,653,1019,
%T 1151,1201,1229,1279,1433,1459,1523,1559,1601,1669,1999,2053,2153,
%U 2203,2207,2357,3061,3643,3671,4127,4447,4603,5099,5507,5651,5701,5813,6079
%N Primes p such that 2*p^2+-9 are also prime.
%H Vincenzo Librandi, <a href="/A174357/b174357.txt">Table of n, a(n) for n = 1..1000</a>
%e For p=5, 2*5^2-+9=(41,59); p=7, 2*7^2-+9=(89,107); p=11, 2*11^2-+9=(233,251)
%t Select[Prime[Range[100]], PrimeQ[2 #^2 - 9]&&PrimeQ[2 #^2 + 9]&] (* _Vincenzo Librandi_, Apr 10 2013 *)
%o (Magma) [p: p in PrimesUpTo(10000)|IsPrime(2*p^2-9) and IsPrime(2*p^2+9)]
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Mar 17 2010
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