A060756 a(n) is the smallest number for which exactly n primes are bounded between a(n) and 2a(n) exclusively.

1, 2, 4, 9, 10, 16, 22, 27, 34, 36, 40, 51, 52, 55, 57, 70, 82, 87, 91, 96, 99, 100, 120, 121, 126, 135, 136, 142, 147, 159, 175, 177, 187, 190, 205, 210, 216, 217, 220, 222, 232, 246, 250, 255, 262, 289, 297, 300, 301, 304, 309, 310, 324, 327, 330, 339, 342

Offset: 0

Author

Lekraj Beedassy, Apr 23 2001

Keywords

• nonn

Comments

a(n) is the first occurrence of n in A060715.

Examples

			a(10)=40 since ten primes,namely,41,43,47,53,59,61,67,71,73,79,first arise between 40 and its double.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A060715, A059316, A080359.

Programs

Haskell

import Data.List (elemIndex)
import Data.Maybe (mapMaybe)
a060756 n = a060756_list !! n
a060756_list = map (+ 1) $ mapMaybe (`elemIndex` a060715_list) [0..]
-- Reinhard Zumkeller, Jan 05 2012

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jun 05 2001