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Numbers n such that 1000*n - 1 is prime.
1

%I #14 Sep 08 2022 08:45:17

%S 2,3,5,9,14,26,33,36,42,50,53,57,60,71,72,74,78,80,86,95,99,101,102,

%T 105,108,134,135,137,138,140,144,158,162,165,173,180,183,185,189,192,

%U 200,203,204,213,222,224,231,240,243,248,254,261,267,269,273,276,278,287

%N Numbers n such that 1000*n - 1 is prime.

%H Harvey P. Dale, <a href="/A105044/b105044.txt">Table of n, a(n) for n = 1..1000</a>

%e If n=2, then 1000*n - 1 = 1000*2 - 1 = 1999 (prime).

%e If n=99, then 1000*n - 1 = 1000*99 - 1 = 98999 (prime).

%t Select[Range[300], PrimeQ[1000 # - 1] &] (* _Harvey P. Dale_, Oct 05 2016 *)

%o (Magma) [n: n in [0..100000] | IsPrime(1000*n - 1)] - _Vincenzo Librandi_, Nov 13 2010

%o (PARI) is(n)=isprime(1000*n-1) \\ _Charles R Greathouse IV_, Jun 12 2017

%K nonn,easy

%O 1,1

%A _Parthasarathy Nambi_, Apr 03 2005