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 A023286 Numbers n such that n remains prime through 3 iterations of function f(x) = 5x + 8. 3
 7, 13, 43, 223, 757, 883, 2143, 2269, 2521, 2917, 3253, 3967, 4297, 4423, 6229, 6427, 6679, 7621, 7741, 10429, 11353, 12739, 14593, 14929, 15259, 15541, 15937, 16981, 17449, 17911, 21187, 23899, 24697, 25633, 27481, 28789, 29611, 29833, 30253, 30703 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Numbers n such that n, 5*n+8, 25*n+48 and 125*n+248 are primes. - Vincenzo Librandi, Aug 04 2010 LINKS John Cerkan, Table of n, a(n) for n = 1..10000 FORMULA a(n) == 1 (mod 6). - John Cerkan, Sep 21 2016 MATHEMATICA it3Q[n_]:=AllTrue[Rest[NestList[5#+8&, n, 3]], PrimeQ]; Select[ Prime[ Range[ 3500]], it3Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 21 2015 *) PROG (MAGMA) [n: n in [1..150000] | IsPrime(n) and IsPrime(5*n+8) and IsPrime(25*n+48) and IsPrime(125*n+248)] // Vincenzo Librandi, Aug 04 2010 CROSSREFS Subsequence of A023220, A023255, and A111225. Sequence in context: A139403 A087820 A272032 * A287685 A159305 A146648 Adjacent sequences:  A023283 A023284 A023285 * A023287 A023288 A023289 KEYWORD nonn AUTHOR STATUS approved

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Last modified February 18 02:57 EST 2020. Contains 332006 sequences. (Running on oeis4.)