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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

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OFFSET

0,2

COMMENTS

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

LINKS

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

EXAMPLE

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

PROG

(Haskell)

import Data.List (elemIndex)