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A023260 Numbers n such that n remains prime through 2 iterations of function f(x) = 8x + 1. 3
2, 17, 101, 107, 401, 821, 947, 1151, 1487, 2027, 2207, 2411, 2741, 2927, 3851, 4391, 4691, 5231, 5861, 6701, 7001, 8297, 8807, 9341, 9587, 9851, 10067, 11117, 11447, 11897, 12107, 12911, 16187, 17657, 20681, 20771, 20807, 21221, 21227, 21491, 21521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 8*n+1 and 64*n+9 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

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

MATHEMATICA

Select[Prime[Range[2500]], And@@PrimeQ[Rest[NestList[8#+1&, #, 2]]]&] (* Harvey P. Dale, Jan 26 2013 *)

PROG

(MAGMA) [n: n in [1..100000] | IsPrime(n) and IsPrime(8*n+1) and IsPrime(64*n+9)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Sequence in context: A129123 A109724 A127533 * A174365 A119363 A272065

Adjacent sequences:  A023257 A023258 A023259 * A023261 A023262 A023263

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified June 25 05:41 EDT 2019. Contains 324346 sequences. (Running on oeis4.)