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A023249 Numbers n such that n remains prime through 2 iterations of function f(x) = 3x + 10. 3
3, 7, 11, 17, 19, 47, 67, 109, 149, 151, 199, 227, 233, 347, 353, 359, 397, 431, 457, 487, 563, 571, 577, 607, 709, 809, 919, 947, 997, 1013, 1033, 1069, 1103, 1117, 1151, 1187, 1279, 1361, 1367, 1451, 1601, 1607, 1697, 1699, 1801, 1811, 1823, 1831, 1871, 1913 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 3*n+10, 9*n+40 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

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

MATHEMATICA

Select[Range@ 2000, Times @@ Boole@ PrimeQ@ NestList[3 # + 10 &, #, 2] > 0 &] (* Michael De Vlieger, Sep 13 2016 *)

PROG

(MAGMA) [n: n in [0..100000] | IsPrime(n) and IsPrime(3*n+10) and IsPrime(9*n+40)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Subsequence of A023211.

Sequence in context: A045419 A049098 A119992 * A249682 A090513 A285600

Adjacent sequences:  A023246 A023247 A023248 * A023250 A023251 A023252

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified January 25 19:09 EST 2020. Contains 331249 sequences. (Running on oeis4.)