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A288921
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Lexicographically earliest sequence of distinct positive terms such that the product of two consecutive terms has at least 34 divisors.
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3
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1, 1260, 2, 630, 4, 315, 8, 180, 7, 240, 6, 210, 10, 126, 16, 90, 14, 120, 12, 105, 20, 63, 32, 45, 28, 60, 21, 80, 18, 70, 24, 75, 36, 35, 48, 30, 42, 40, 54, 50, 66, 56, 72, 25, 84, 15, 96, 33, 100, 27, 112, 39, 132, 49, 108, 44, 117, 64, 81, 88, 78, 98, 99
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OFFSET
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1,2
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COMMENTS
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The number of divisors is given by A000005.
This sequence is a permutation of the natural numbers, with inverse A288922.
Conjecturally, a(n) ~ n.
See also A288923 for similar sequences.
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LINKS
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EXAMPLE
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The first terms, alongside a(n)*a(n+1) and its number of divisors, are:
n a(n) a(n)*a(n+1) Number of divisors
-- ---- ----------- ------------------
1 1 1260 36
2 1260 2520 48
3 2 1260 36
4 630 2520 48
5 4 1260 36
6 315 2520 48
7 8 1440 36
8 180 1260 36
9 7 1680 40
10 240 1440 36
11 6 1260 36
12 210 2100 36
13 10 1260 36
14 126 2016 36
15 16 1440 36
16 90 1260 36
17 14 1680 40
18 120 1440 36
19 12 1260 36
20 105 2100 36
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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