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

0,1

Comments

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

Links

Table of n, a(n) for n=0..38.

Formula

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

Example

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

Crossrefs

Sequence in context: A307317 A188669 A243568 * A004252 A114957 A002773

Adjacent sequences: A087375 A087376 A087377 * A087379 A087380 A087381

Keyword

nonn

Author

Amarnath Murthy, Sep 09 2003

Extensions

More terms from David Wasserman, May 24 2005

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

Status

approved