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Primes that remain prime through 2 iterations of function f(x) = 4x + 3.
2

%I #27 Sep 08 2022 08:44:47

%S 2,7,11,37,67,89,109,149,179,257,439,467,571,677,691,719,929,977,1019,

%T 1279,1381,1447,1549,1567,1747,1787,1901,1931,2111,2161,2207,2287,

%U 2347,2377,2459,2539,2671,2711,2819,3119,3229,3371,3491,3607,3637,3821,3877

%N Primes that remain prime through 2 iterations of function f(x) = 4x + 3.

%C Primes p such that 4*p+3 and 16*p+15 are also primes. - _Vincenzo Librandi_, Aug 04 2010

%H John Cerkan, <a href="/A023250/b023250.txt">Table of n, a(n) for n = 1..10000</a>

%p A023250:=n->`if`(isprime(n) and isprime(4*n+3) and isprime(16*n+15), n, NULL): seq(A023250(n), n=1..10^4); # _Wesley Ivan Hurt_, Feb 12 2017

%t Select[Range@ 3900, Times @@ Boole@ PrimeQ@ NestList[4 # + 3 &, #, 2] > 0 &] (* _Michael De Vlieger_, Sep 13 2016 *)

%o (Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(4*n+3) and IsPrime(16*n+15)] // _Vincenzo Librandi_, Aug 04 2010

%Y Subsequence of A095278.

%K nonn

%O 1,1

%A _David W. Wilson_