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A023276 Primes that remain prime through 3 iterations of function f(x) = 2x + 9.

%I A023276 #27 Sep 08 2022 08:44:47
%S A023276 5,11,31,71,281,521,911,1181,2371,2521,3391,3701,4211,4931,5051,7211,
%T A023276 7411,8221,8431,8461,8501,8641,8951,9601,9871,10301,11981,12421,13121,
%U A023276 13921,14591,16381,16451,16901,16931,17791,17881,19391,19751,21991,23021
%N A023276 Primes that remain prime through 3 iterations of function f(x) = 2x + 9.
%C A023276 Primes p such that 2*p+9, 4*p+27 and 8*p+63 are also primes. - _Vincenzo Librandi_, Aug 04 2010
%H A023276 John Cerkan, <a href="/A023276/b023276.txt">Table of n, a(n) for n = 1..10000</a>
%F A023276 a(n) == 1 (mod 10) for n > 1. - _John Cerkan_, Sep 16 2016
%p A023276 A023276:=n->`if`(isprime(n) and isprime(2*n+9) and isprime(4*n+27) and isprime(8*n+63), n, NULL): seq(A023276(n), n=1..10^5); # _Wesley Ivan Hurt_, Feb 11 2017
%t A023276 Select[Prime@ Range@ 2600, Times @@ Boole@ PrimeQ@ Rest@ NestList[2 # + 9 &, #, 3] > 0 &] (* _Michael De Vlieger_, Sep 19 2016 *)
%t A023276 Select[Prime[Range[3000]],AllTrue[Rest[NestList[2#+9&,#,3]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jan 01 2017 *)
%o A023276 (Magma) [n: n in [1..100000] | IsPrime(n) and IsPrime(2*n+9) and IsPrime(4*n+27) and IsPrime(8*n+63)] // _Vincenzo Librandi_, Aug 04 2010
%o A023276 (PARI) is(n)=isprime(n) && isprime(2*n+9) && isprime(4*n+27) && isprime(8*n+63) \\ _Charles R Greathouse IV_, Sep 20 2016
%Y A023276 Subsequence of A023207, A023245, and of A155722.
%K A023276 nonn
%O A023276 1,1
%A A023276 _David W. Wilson_