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A023269 Numbers n such that n remains prime through 2 iterations of function f(x) = 10x + 3. 1
2, 7, 17, 19, 23, 37, 61, 67, 73, 101, 103, 173, 193, 233, 359, 383, 409, 479, 541, 557, 607, 613, 719, 809, 857, 997, 1013, 1033, 1109, 1117, 1237, 1297, 1361, 1459, 1531, 1549, 1699, 1823, 1871, 1979, 1999, 2069, 2131, 2161, 2347, 2377, 2399, 2447, 2663 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

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

MATHEMATICA

Select[Prime@ Range@ 400, Times @@ Boole@ PrimeQ@ Rest@ NestList[10 # + 3 &, #, 2] > 0 &] (* Michael De Vlieger, Sep 16 2016 *)

Select[Prime[Range[500]], AllTrue[Rest[NestList[10#+3&, #, 2]], PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 03 2018 *)

PROG

(MAGMA) [n: n in [1..100000] | IsPrime(n) and IsPrime(10*n+3) and IsPrime(100*n+33)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Subsequence of A023238 and of A102338.

Sequence in context: A079815 A325510 A006883 * A023300 A317308 A045378

Adjacent sequences:  A023266 A023267 A023268 * A023270 A023271 A023272

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified November 20 20:28 EST 2019. Contains 329347 sequences. (Running on oeis4.)