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A023356 Numbers n such that n remains prime through 5 iterations of the function f(x) = 10x + 3. 1
10061, 20071, 161093, 200713, 291419, 564979, 600791, 606839, 693079, 1826519, 1876807, 2106407, 2249207, 2471471, 3335369, 3955499, 4542547, 4765609, 4829603, 4955981, 5090507, 5534993, 5866247, 5987921, 6091213, 6399521, 6519613, 6522539 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 10*n+3, 100*n+33, 1000*n+333, 10000*n+3333 and 100000*n+33333 are primes. - Vincenzo Librandi, Aug 05 2010

LINKS

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

FORMULA

a(n) == 9 (mod 14). - John Cerkan, Aug 26 2016

MATHEMATICA

ok5Q[n_]:=And@@PrimeQ/@Rest[NestList[10#+3&, n, 5]]; Select[Prime[ Range[500000]], ok5Q]  (* Harvey P. Dale, Mar 28 2011 *)

PROG

(MAGMA) [n: n in [1..19000000] | IsPrime(n) and IsPrime(10*n+3) and IsPrime(100*n+33) and IsPrime(1000*n+333) and IsPrime(10000*n+3333) and IsPrime(100000*n+33333)] // Vincenzo Librandi, Aug 05 2010

(PARI) is(n)=isprime(n) && isprime(10*n+3) && isprime(100*n+33) && isprime(1000*n+333) && isprime(10000*n+3333) && isprime(100000*n+33333) \\ Charles R Greathouse IV, Jul 28 2016

CROSSREFS

Sequence in context: A223431 A203089 A187113 * A292176 A198484 A252200

Adjacent sequences:  A023353 A023354 A023355 * A023357 A023358 A023359

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified April 5 03:15 EDT 2020. Contains 333238 sequences. (Running on oeis4.)