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A023353 Primes that remain prime through 5 iterations of the function f(x) = 9x + 4. 1
421, 773, 1567, 4111, 68447, 75721, 111373, 127301, 137927, 140321, 156593, 170767, 177131, 192341, 194687, 202637, 240641, 254407, 254963, 308303, 321821, 332951, 395431, 464131, 515663, 710081, 822893, 856393, 989533, 997123, 1012201, 1047077 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes p such that 9*p+4, 81*p+40, 729*p+364, 6561*p+3280 and 59049*p+29524 are also primes. - Vincenzo Librandi, Aug 05 2010

LINKS

John Cerkan, Table of n, a(n) for n = 1..10000

MATHEMATICA

okQ[n_]:=And@@PrimeQ/@Rest[NestList[9#+4&, n, 5]]; Select[Prime[Range[100000]], okQ]  (* Harvey P. Dale, Jan 29 2011 *)

PROG

(Magma) [n: n in [1..19000000] | IsPrime(n) and IsPrime(9*n+4) and IsPrime(81*n+40) and IsPrime(729*n+364) and IsPrime(6561*n+3280) and IsPrime(59049*n+29524)] // Vincenzo Librandi, Aug 05 2010

CROSSREFS

Subsequence of A023234, A023266, A023297, and A023325.

Sequence in context: A146358 A050962 A020376 * A142853 A217587 A068701

Adjacent sequences:  A023350 A023351 A023352 * A023354 A023355 A023356

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified October 1 13:29 EDT 2022. Contains 357149 sequences. (Running on oeis4.)