|
%I #21 Sep 08 2022 08:44:47
%S 293,2063,4583,9203,14723,20123,25733,29453,40253,54713,76103,97523,
%T 99833,109433,138683,149993,158243,196853,199403,218873,253103,297623,
%U 379913,416963,445463,468113,508073,551963,562403,564713,574703,583733
%N Primes that remain prime through 4 iterations of function f(x) = 2x + 7.
%C Primes p such that 2*p+7, 4*p+21, 8*p+49 and 16*p+105 are also primes. - _Vincenzo Librandi_, Aug 04 2010
%H John Cerkan, <a href="/A023305/b023305.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) == 3 (mod 10). - _John Cerkan_, Oct 04 2016
%t rp4Q[n_]:=AllTrue[Rest[NestList[2#+7&,n,4]],PrimeQ]; Select[Prime[Range[ 50000]],rp4Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Mar 30 2020 *)
%o (Magma) [n: n in [1..1000000] | IsPrime(n) and IsPrime(2*n+7) and IsPrime(4*n+21) and IsPrime(8*n+49) and IsPrime(16*n+105)] // _Vincenzo Librandi_, Aug 04 2010
%Y Subsequence of A023206, A023244, A023275, and A105760.
%K nonn
%O 1,1
%A _David W. Wilson_
|
