The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A023320 Numbers n such that n remains prime through 4 iterations of function f(x) = 8x + 3. 2

%I

%S 13121,117281,188831,317971,429281,624721,627791,722431,774791,883721,

%T 924731,946291,1002721,1083851,1212011,1221601,1249111,1342361,

%U 1469761,1665761,1896901,2003081,2156251,2336011,2382761,2391451,2612021,2634551

%N Numbers n such that n remains prime through 4 iterations of function f(x) = 8x + 3.

%C n, 8*n+3, 64*n+27, 512*n+219 and 4096*n+1755 are primes. - _Vincenzo Librandi_, Aug 04 2010

%H Harvey P. Dale, <a href="/A023320/b023320.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime[Range[200000]],AllTrue[Rest[NestList[8#+3&,#,4]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Oct 04 2015 *)

%o (MAGMA) [n: n in [1..5000000] | IsPrime(n) and IsPrime(8*n+3) and IsPrime(64*n+27) and IsPrime(512*n+219) and IsPrime(4096*n+1755)] // _Vincenzo Librandi_, Aug 04 2010

%K nonn

%O 1,1

%A _David W. Wilson_

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 9 04:39 EDT 2020. Contains 336319 sequences. (Running on oeis4.)