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A023284 Numbers n such that n remains prime through 3 iterations of function f(x) = 5x + 4. 3
83, 263, 1217, 1319, 1511, 1721, 1847, 1907, 2141, 2531, 4283, 4673, 5333, 6089, 6353, 6983, 7013, 7151, 7529, 8543, 10709, 10973, 11423, 15077, 15137, 17387, 17573, 20129, 20201, 20411, 20663, 21521, 23369, 23561, 25343, 26669, 27143, 27647, 28697 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 5*n+4, 25*n+24 and 125*n+124 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

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

MATHEMATICA

Select[Prime[Range[3500]], And@@PrimeQ[Rest[NestList[5#+4&, #, 3]]]&] (* Harvey P. Dale, Feb 01 2013 *)

PROG

(MAGMA) [n: n in [1..150000] | IsPrime(n) and IsPrime(5*n+4) and IsPrime(25*n+24) and IsPrime(125*n+124)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Sequence in context: A238680 A008897 A159071 * A142025 A142387 A145651

Adjacent sequences:  A023281 A023282 A023283 * A023285 A023286 A023287

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified September 19 07:24 EDT 2020. Contains 337178 sequences. (Running on oeis4.)