A060756 - OEIS

%I #17 Mar 03 2019 04:23:18

%S 1,2,4,9,10,16,22,27,34,36,40,51,52,55,57,70,82,87,91,96,99,100,120,

%T 121,126,135,136,142,147,159,175,177,187,190,205,210,216,217,220,222,

%U 232,246,250,255,262,289,297,300,301,304,309,310,324,327,330,339,342

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

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

%H Reinhard Zumkeller, <a href="/A060756/b060756.txt">Table of n, a(n) for n = 0..10000</a>

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

%o (Haskell)

%o import Data.List (elemIndex)

%o import Data.Maybe (mapMaybe)

%o a060756 n = a060756_list !! n

%o a060756_list = map (+ 1) $ mapMaybe (`elemIndex` a060715_list) [0..]

%o -- _Reinhard Zumkeller_, Jan 05 2012

%Y Cf. A060715, A059316, A080359.

%K nonn

%O 0,2

%A _Lekraj Beedassy_, Apr 23 2001

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