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Primes p such that p + 30 is not a prime.
1

%I #29 Sep 08 2022 08:45:34

%S 2,3,5,19,47,61,89,103,113,131,139,157,173,179,191,223,229,257,269,

%T 271,293,311,313,331,347,373,383,397,421,439,443,463,467,487,499,503,

%U 509,521,523,593,599,607,619,641,659,673,677,683,691,701,719,733,751,761

%N Primes p such that p + 30 is not a prime.

%H Daniel Starodubtsev, <a href="/A140560/b140560.txt">Table of n, a(n) for n = 1..10000</a>

%p A140560:=n->`if`(isprime(n) and not isprime(n+30), n, NULL): seq(A140560(n), n=1..2*10^3); # _Wesley Ivan Hurt_, Apr 14 2017

%t Select[Prime[Range[200]],!PrimeQ[#+30]&] (* _Harvey P. Dale_, Oct 21 2013 *)

%o (Magma)[p: p in PrimesUpTo(1000)|not IsPrime(p+30)] // _Vincenzo Librandi_, Dec 18 2010

%o (PARI) isok(n) = isprime(n) && !isprime(n+30); \\ _Michel Marcus_, Apr 14 2017

%o (Python)

%o from sympy import isprime, primerange

%o print([p for p in primerange(1, 1001) if not isprime(p + 30)]) # _Indranil Ghosh_, Apr 14 2017

%Y Cf. A049481.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Jul 03 2008

%E Corrected (3, 5 inserted) by _R. J. Mathar_, Apr 25 2010