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A367035
Numbers k such that the greatest prime less than 2*k is less than twice the greatest prime less than k.
3
8, 14, 18, 20, 32, 33, 38, 39, 44, 48, 60, 61, 62, 63, 68, 72, 73, 74, 80, 81, 98, 102, 103, 104, 105, 108, 109, 110, 111, 128, 138, 140, 150, 151, 152, 153, 158, 164, 165, 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
OFFSET
1,1
COMMENTS
Numbers k such that A049711(2 * k) > 2 * A049711(k).
LINKS
EXAMPLE
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.
MAPLE
select(k -> prevprime(2*k) < 2*prevprime(k), [$3..300]);
PROG
(PARI) isok(k) = precprime(2*k-1) < 2*precprime(k-1); \\ Michel Marcus, Dec 16 2023
CROSSREFS
Includes k+1 for k in A053176. Disjoint from A006254.
Sequence in context: A084021 A138666 A072835 * A096229 A231718 A212020
KEYWORD
nonn
AUTHOR
Robert Israel, Dec 15 2023
STATUS
approved