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 A243012 Odd primes p such that neither p - 4 nor p + 4 is prime. 0

%I

%S 5,29,31,53,59,61,73,89,137,139,149,151,157,173,179,181,191,199,211,

%T 239,241,251,257,263,269,271,283,293,331,337,347,359,367,373,389,409,

%U 419,421,431,433,449,479,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,619

%N Odd primes p such that neither p - 4 nor p + 4 is prime.

%F a(n) ~ n log n. - _Charles R Greathouse IV_, May 29 2014

%e 5 is in this sequence because 5 is prime and neither 5 - 4 = 1 nor 5 + 4 = 9 is prime.

%t Select[Prime[Range[125]], Not[PrimeQ[# - 4]] && Not[PrimeQ[# + 4]] &] (* _Alonso del Arte_, May 30 2014 *)

%o (MAGMA) [p: p in PrimesUpTo(620) | not IsPrime(p-4) and not IsPrime(p+4)];

%o (PARI) select(n->!isprime(n-4) && !isprime(n+4), primes(200)) \\ _Charles R Greathouse IV_, May 29 2014

%o (Sage) [p for p in primes(5,700) if not is_prime(p-4) and not is_prime(p+4)] # _Bruno Berselli_, Jun 10 2014

%Y Cf. A007510, A140546.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, May 28 2014

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Last modified April 5 17:03 EDT 2020. Contains 333245 sequences. (Running on oeis4.)