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A073085 Numbers n such that 210*n+1 is prime. 2

%I

%S 1,2,3,5,7,11,12,13,16,17,20,22,23,28,29,30,35,36,39,42,44,46,47,50,

%T 51,53,55,57,59,60,64,67,68,72,73,74,78,81,83,85,86,88,89,93,96,100,

%U 101,104,105,111,115,117,118,121,122,124,125,128,129,135,137,139,140,141

%N Numbers n such that 210*n+1 is prime.

%H Vincenzo Librandi, <a href="/A073085/b073085.txt">Table of n, a(n) for n = 1..1000</a>

%e 1 is a member because 210*1+1=211 is prime; 100 is a member because 210*100+1=21001 is prime.

%t Flatten[Position[PrimeQ[210Range[100]+1], True]]

%t Select[Range[150], PrimeQ[(210*# + 1)] &] (* _Vincenzo Librandi_, Sep 30 2012 *)

%o (MAGMA) [n: n in [1..200] | IsPrime(210*n + 1)]; _Vincenzo Librandi_, Sep 30 2012

%o (PARI) is(n)=isprime(210*n+1) \\ _Charles R Greathouse IV_, May 22 2017

%Y Cf. A073102.

%K easy,nonn

%O 1,2

%A _Zak Seidov_, Oct 08 2002

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Last modified October 23 11:52 EDT 2021. Contains 348212 sequences. (Running on oeis4.)