A087378 Smallest k such that both k-n and k+n are primes and there are no primes between them.

2, 4, 9, 26, 93, 144, 205, 120, 1839, 532, 897, 1140, 1681, 2490, 2985, 4312, 5607, 1344, 9569, 30612, 19353, 16162, 15705, 81486, 28253, 31932, 19635, 35644, 82101, 44322, 43361, 34092, 89721, 162176, 134547, 173394, 31433, 404634, 212739

Offset: 0

Author

Amarnath Murthy, Sep 09 2003

Keywords

• nonn

Comments

For n>0, a(n) = arithmetic mean of the smallest pair of two consecutive primes with a difference 2n.

Examples

			a(5) = 144 as 139 and 149 both are prime and all numbers from 140 to 148 are composite.
		

Formula

a(n) = A000230(n)+n. - David Wasserman, May 24 2005

Extensions

More terms from David Wasserman, May 24 2005

Edited by Franklin T. Adams-Watters, Oct 26 2006