A102700 Numbers k such that 10*k + 9 is prime.

1, 2, 5, 7, 8, 10, 13, 14, 17, 19, 22, 23, 26, 34, 35, 37, 38, 40, 41, 43, 44, 47, 49, 50, 56, 59, 61, 65, 70, 71, 73, 76, 80, 82, 83, 85, 91, 92, 100, 101, 103, 104, 106, 110, 112, 122, 124, 125, 127, 128, 131, 139, 140, 142, 143, 145, 148, 149, 154, 155, 157, 160, 161

Offset: 1

Author

Parthasarathy Nambi, Feb 04 2005

Keywords

• base
• nonn

Examples

			10*1 + 9 = 19 (prime);
10*40 + 9 = 409 (prime);
10*70 + 9 = 709 (prime).
		

Links

• Daniel Starodubtsev, Table of n, a(n) for n = 1..10000
• Chris Caldwell, The first 1,000 primes.

Crossrefs

Cf. A030433, A049510.

Programs

Magma

[n: n in [0..3000]| IsPrime(10*n+9)]; // Vincenzo Librandi, Apr 06 2011

Mathematica

Select[Range[0, 170], PrimeQ[10# + 9] &] (* Ray Chandler, Nov 07 2006 *)

PARI

is(n)=isprime(10*n+9) \\ Charles R Greathouse IV, Feb 17 2017

Extensions

Edited and extended by Ray Chandler, Nov 07 2006