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A365059 a(1) = 2; for n > 2, a(n) is the smallest positive number that has not yet appeared that is a multiple of A008472(a(n-1)), the sum of the distinct primes dividing a(n-1). 3
2, 4, 6, 5, 10, 7, 14, 9, 3, 12, 15, 8, 16, 18, 20, 21, 30, 40, 28, 27, 24, 25, 35, 36, 45, 32, 22, 13, 26, 60, 50, 42, 48, 55, 64, 34, 19, 38, 63, 70, 56, 54, 65, 72, 75, 80, 49, 77, 90, 100, 84, 96, 85, 44, 39, 112, 81, 33, 98, 99, 126, 108, 95, 120, 110, 144, 105, 135, 88, 52, 150, 130, 140 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
In the first 500000 terms the only fixed points are 38 and 209, although it is likely more exist. In the same range the smallest missing numbers are 311, 313, 337. The sequence is conjectured to be a permutation of the integers >= 2.
LINKS
Scott R. Shannon, Image of the first 500000 terms. The green line is a(n) = n.
EXAMPLE
a(3) = 6 as a(2) = 4 and A008472(4) = 2, and 6 is the smallest unused number that is a multiple of 2.
a(11) = 15 as a(10) = 12 and A008472(12) = 5, and 15 is the smallest unused number that is a multiple of 5.
CROSSREFS
Sequence in context: A179225 A367711 A365060 * A083718 A319804 A055948
KEYWORD
nonn
AUTHOR
Scott R. Shannon, Aug 19 2023
STATUS
approved

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Last modified June 10 10:32 EDT 2024. Contains 373264 sequences. (Running on oeis4.)