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A023316 Numbers n such that n remains prime through 4 iterations of function f(x) = 5x + 8. 2
7, 43, 883, 2269, 2917, 7621, 15541, 15937, 36541, 38113, 54787, 60961, 67033, 71359, 77491, 79693, 82531, 84967, 112621, 129589, 176461, 185683, 192547, 239671, 248071, 267373, 271489, 271549, 310231, 316471, 340957, 343267, 350617, 382303 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

n, 5*n+8, 25*n+48, 125*n+248 and 625*n+1248 are primes. - Vincenzo Librandi, Aug 04 2010

LINKS

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

FORMULA

a(n) == 1 or 19 (mod 42) for n > 1. - John Cerkan, Oct 07 2016

PROG

(MAGMA) [n: n in [1..1000000] | IsPrime(n) and IsPrime(5*n+8) and IsPrime(25*n+48) and IsPrime(125*n+248) and IsPrime(625*n+1248)] // Vincenzo Librandi, Aug 04 2010

(PARI) is(n)=isprime(n) && isprime(5*n+8) && isprime(25*n+48) && isprime(125*n+248) && isprime(625*n+1248) \\ Charles R Greathouse IV, Oct 08 2016

CROSSREFS

Subsequence of A023220, A023255, A023286, and A111225.

Sequence in context: A195230 A316635 A222981 * A289737 A065786 A015463

Adjacent sequences:  A023313 A023314 A023315 * A023317 A023318 A023319

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified September 29 05:48 EDT 2020. Contains 337425 sequences. (Running on oeis4.)