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A085555 Primes p of the form x^2+4, such that either p-2 or p+2 is prime. 1

%I

%S 5,13,29,229,1093,1229,2029,3253,4229,13693,21613,59053,65029,91813,

%T 140629,178933,199813,205213,227533,328333,366029,567013,700573,

%U 804613,815413,819029,1071229,1155629,1311029,1575029,2241013,3629029,3822029

%N Primes p of the form x^2+4, such that either p-2 or p+2 is prime.

%H Robert Israel, <a href="/A085555/b085555.txt">Table of n, a(n) for n = 1..10000</a>

%p select(t -> isprime(t) and (isprime(t+2) or isprime(t-2)), [seq(x^2+4,x=1..10^4,2)]); # _Robert Israel_, May 14 2018

%t okQ[n_]:=PrimeQ[n]&&(PrimeQ[n-2]||PrimeQ[n+2]); Select[Range[ 2000]^2+4, okQ] (* _Harvey P. Dale_, Jul 14 2011 *)

%K easy,nonn

%O 1,1

%A _Cino Hilliard_, Jul 04 2003

%E Edited by _Don Reble_, May 03 2006

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Last modified September 22 02:48 EDT 2021. Contains 347605 sequences. (Running on oeis4.)