cp's OEIS Frontend

A367035 Numbers k such that the greatest prime less than 2*k is less than twice the greatest prime less than k.

%I A367035 #30 Dec 16 2023 13:10:59
%S A367035 8,14,18,20,32,33,38,39,44,48,60,61,62,63,68,72,73,74,80,81,98,102,
%T A367035 103,104,105,108,109,110,111,128,138,140,150,151,152,153,158,164,165,
%U A367035 168,182,183,194,198,200,212,213,214,215,224,228,230,242,243,258,259,260,264,265,266,267,268,269,270
%N A367035 Numbers k such that the greatest prime less than 2*k is less than twice the greatest prime less than k.
%C A367035 Numbers k such that A049711(2 * k) > 2 * A049711(k).
%H A367035 Robert Israel, <a href="/A367035/b367035.txt">Table of n, a(n) for n = 1..10000</a>
%e A367035 a(3) = 18 is a term because the greatest prime < 18 is 17, the greatest prime < 2*18 = 36 is 31, and 31 < 2 * 17.
%p A367035 select(k -> prevprime(2*k) < 2*prevprime(k), [$3..300]);
%o A367035 (PARI) isok(k) = precprime(2*k-1) < 2*precprime(k-1); \\ _Michel Marcus_, Dec 16 2023
%Y A367035 Includes k+1 for k in A053176. Disjoint from A006254.
%Y A367035 Cf. A049711, A151799.
%K A367035 nonn
%O A367035 1,1
%A A367035 _Robert Israel_, Dec 15 2023