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A023320 Numbers n such that n remains prime through 4 iterations of function f(x) = 8x + 3. 2
13121, 117281, 188831, 317971, 429281, 624721, 627791, 722431, 774791, 883721, 924731, 946291, 1002721, 1083851, 1212011, 1221601, 1249111, 1342361, 1469761, 1665761, 1896901, 2003081, 2156251, 2336011, 2382761, 2391451, 2612021, 2634551 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 8*n+3, 64*n+27, 512*n+219 and 4096*n+1755 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

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 *)

PROG

(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

CROSSREFS

Sequence in context: A250948 A157433 A089212 * A206149 A221156 A068760

Adjacent sequences:  A023317 A023318 A023319 * A023321 A023322 A023323

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified July 5 00:40 EDT 2020. Contains 335457 sequences. (Running on oeis4.)