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Primes p such that p^2 + 2*p + 4 is prime.
1

%I #14 Jan 11 2022 12:33:37

%S 3,7,13,37,61,73,139,157,229,241,349,367,397,433,439,457,523,541,601,

%T 619,709,727,751,769,787,859,919,1069,1129,1153,1237,1381,1459,1609,

%U 1627,1699,1783,1801,2029,2221,2239,2347,2467,2557,2659,2719,2767,3001,3019,3253,3331,3391,3547,3673,3691

%N Primes p such that p^2 + 2*p + 4 is prime.

%H Robert Israel, <a href="/A350676/b350676.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3) = 13 is a term because 13 and 13^2 + 2*13 + 4 = 199 are prime.

%p select(p -> isprime(p^2+2*p+4), [seq(ithprime(i),i=1..1000)]);

%o (Python)

%o from sympy import isprime

%o for p in range (2,3700):

%o if isprime(p) and isprime(p**2 + 2*p + 4):

%o print (p, end=", ") # _Karl-Heinz Hofmann_, Jan 11 2022

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Jan 10 2022