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A023324 Numbers n such that n remains prime through 4 iterations of function f(x) = 9x + 2. 2
103, 283, 313, 929, 2549, 2593, 3931, 4091, 5279, 6781, 7759, 8363, 16229, 16493, 16703, 19961, 24071, 25733, 27059, 32191, 34961, 35381, 36341, 44131, 50093, 52973, 59671, 66179, 69833, 69931, 75853, 90031, 92993, 93371, 101879, 103561, 106949 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 9*n+2, 81*n+20, 729*n+182 and 6561*n+1640 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

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

MATHEMATICA

Select[Prime[Range[11000]], AllTrue[Rest[NestList[9#+2&, #, 4]], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 12 2015 *)

PROG

(MAGMA) [n: n in [1..5000000] | IsPrime(n) and IsPrime(9*n+2) and IsPrime(81*n+20) and IsPrime(729*n+182) and IsPrime(6561*n+1640)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Sequence in context: A252261 A141992 A023327 * A034846 A023352 A142476

Adjacent sequences:  A023321 A023322 A023323 * A023325 A023326 A023327

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified July 22 16:43 EDT 2019. Contains 325225 sequences. (Running on oeis4.)