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

1, 2, 3, 5, 7, 11, 12, 13, 16, 17, 20, 22, 23, 28, 29, 30, 35, 36, 39, 42, 44, 46, 47, 50, 51, 53, 55, 57, 59, 60, 64, 67, 68, 72, 73, 74, 78, 81, 83, 85, 86, 88, 89, 93, 96, 100, 101, 104, 105, 111, 115, 117, 118, 121, 122, 124, 125, 128, 129, 135, 137, 139, 140, 141

Offset: 1

Author

Zak Seidov, Oct 08 2002

Keywords

• easy
• nonn

Examples

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

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A073102.

Programs

Magma

[n: n in [1..200] | IsPrime(210*n + 1)]; Vincenzo Librandi, Sep 30 2012

Mathematica

Flatten[Position[PrimeQ[210Range[100]+1], True]]
Select[Range[150], PrimeQ[(210*# + 1)] &] (* Vincenzo Librandi, Sep 30 2012 *)

PARI

is(n)=isprime(210*n+1) \\ Charles R Greathouse IV, May 22 2017