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A356441
Numbers k such that A309892(k) < k/gpf(k), where gpf = A006530; complement of A356438.
3
8, 16, 18, 24, 27, 32, 36, 40, 45, 48, 50, 54, 60, 64, 72, 75, 80, 81, 84, 90, 96, 98, 100, 105, 108, 112, 120, 125, 126, 128, 135, 140, 144, 147, 150, 154, 160, 162, 165, 168, 175, 176, 180, 189, 192, 196, 198, 200, 210, 216, 220, 224, 225, 231, 234, 240, 242, 243
OFFSET
1,1
COMMENTS
k is a term if and only if k/gpf(k) > nextprime(gpf(k)), where nextprime = A151800.
LINKS
Jianing Song, Table of n, a(n) for n = 1..13098 (all terms <= 50000)
EXAMPLE
8 is a term since the number of steps needed to reach 0 of the iteration x -> x - gpf(x) starting at 8 is 3: 8 -> 6 -> 3 -> 0, and 3 < 8/gpf(8).
PROG
(PARI) isA356441(n) = if(n>1, my(p=vecmax(factor(n)[, 1])); n/p>nextprime(p+1), 0)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jianing Song, Aug 07 2022
STATUS
approved