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Primes p such that 20*p - 3 and 20*p + 3 are both primes.
1

%I #17 Sep 08 2022 08:45:17

%S 2,5,13,23,43,61,83,89,107,173,181,223,233,313,317,349,379,467,523,

%T 659,673,727,769,811,911,971,1009,1051,1069,1097,1153,1279,1321,1433,

%U 1451,1549,1559,1583,1693,1777,1861,1993,2029,2063,2137,2213,2267,2357,2441

%N Primes p such that 20*p - 3 and 20*p + 3 are both primes.

%H Michael De Vlieger, <a href="/A106009/b106009.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Prime[Range[200]], PrimeQ[20#+3]&&PrimeQ[20#-3]&]

%o (Magma) [p: p in PrimesUpTo(2500) | IsPrime(20*p-3) and IsPrime(20*p+3)]; // _Vincenzo Librandi_, Nov 13 2010

%K nonn

%O 1,1

%A _Zak Seidov_, May 05 2005