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A023304 Primes that remain prime through 4 iterations of function f(x) = 2x + 5. 4
13, 31, 181, 541, 661, 1087, 1861, 2179, 2719, 3727, 7459, 8089, 8707, 9109, 10639, 17341, 19333, 22501, 23293, 29287, 32797, 39847, 40387, 42703, 46591, 51613, 53101, 56149, 56809, 57829, 59233, 80779, 87643, 89113, 89413, 91291, 93979, 94261, 98899 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Primes p such that 2*p+5, 4*p+15, 8*p+35 and 16*p+75 are also primes. - Vincenzo Librandi, Aug 04 2010
LINKS
FORMULA
a(n) == 1 (mod 6). - John Cerkan, Sep 27 2016
MATHEMATICA
Select[Prime@ Range[10^4], Times @@ Boole@ PrimeQ@ Rest@ NestList[2 # + 5 &, #, 4] > 0 &] (* Michael De Vlieger, Sep 27 2016 *)
Select[Prime[Range[10000]], AllTrue[Rest[NestList[2#+5&, #, 4]], PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 23 2020 *)
PROG
(Magma) [n: n in [1..1000000] | IsPrime(n) and IsPrime(2*n+5) and IsPrime(4*n+15) and IsPrime(8*n+35) and IsPrime(16*n+75)] // Vincenzo Librandi, Aug 04 2010
CROSSREFS
Subsequence of A023205, A023243, A023274, and A089038.
Sequence in context: A335787 A141837 A299888 * A247837 A346022 A227172
KEYWORD
nonn
AUTHOR
EXTENSIONS
Definition clarified by Harvey P. Dale, Oct 23 2020
STATUS
approved

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Last modified March 29 08:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)