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A023328 Numbers n such that n remains prime through 4 iterations of function f(x) = 10x + 3. 1
2, 10061, 11777, 17489, 17839, 19379, 19441, 20071, 21773, 30809, 32069, 36529, 39511, 40973, 45503, 52223, 66943, 83813, 100613, 112213, 120067, 135089, 144427, 151573, 156887, 161093, 164999, 179111, 179497, 185923, 200713, 219943, 227489 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 10*n+3, 100*n+33, 1000*n+333 and 10000+3333 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

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

MATHEMATICA

p4iQ[n_]:=And@@PrimeQ[NestList[10#+3&, n, 4]]; Select[Prime[Range[21000]], p4iQ] (* Harvey P. Dale, Oct 02 2012 *)

PROG

(MAGMA) [n: n in [1..5000000] | IsPrime(n) and IsPrime(10*n+3) and IsPrime(100*n+33) and IsPrime(1000*n+333) and IsPrime(10000*n+3333)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Sequence in context: A203755 A285692 A086563 * A294324 A134656 A128122

Adjacent sequences:  A023325 A023326 A023327 * A023329 A023330 A023331

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified July 21 06:55 EDT 2019. Contains 325192 sequences. (Running on oeis4.)