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A023273 Numbers n such that n remains prime through 3 iterations of function f(x) = 2x + 3. 0
2, 5, 47, 67, 97, 137, 197, 277, 307, 607, 617, 1307, 1427, 2857, 5717, 6047, 6217, 6257, 6997, 9377, 9787, 9967, 11197, 12097, 13297, 13997, 14347, 16057, 18757, 18947, 20887, 21517, 21587, 21757, 24197, 26227, 28097, 28447, 32117, 33767, 34367, 35117 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes p such that 2*p+3, 4*p+9 and 8*p+21 are also prime. [From Vincenzo Librandi, Aug 04 2010]

LINKS

Table of n, a(n) for n=1..42.

PROG

(MAGMA) [ p: p in PrimesUpTo(50000) | IsPrime(p) and IsPrime(2*p+3) and IsPrime(4*p+9) and IsPrime(8*p+21)] [From Vincenzo Librandi, Aug 04 2010]

CROSSREFS

Sequence in context: A121621 A225147 A119715 * A041729 A078665 A163666

Adjacent sequences:  A023270 A023271 A023272 * A023274 A023275 A023276

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 22 20:46 EDT 2013. Contains 225583 sequences.