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A348485
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Lexicographically earliest sequence of positive integers in which, for all positive k, there are exactly k contiguous pairs whose product is k, and a(k) * a(k+1) <> a(k+1) * a(k+2).
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2
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1, 1, 2, 2, 1, 3, 2, 2, 3, 1, 4, 2, 2, 3, 1, 5, 2, 3, 3, 2, 4, 3, 2, 4, 3, 3, 4, 2, 5, 1, 7, 2, 4, 3, 3, 4, 2, 5, 1, 7, 2, 4, 3, 3, 4, 2, 5, 1, 7, 2, 5, 1, 7, 2, 5, 3, 3, 4, 4, 3, 3, 4, 4, 3, 3, 4, 4, 5, 2, 7, 1, 9, 2, 5, 3, 3, 5, 2, 7, 1, 10, 2, 7, 1, 11, 2
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listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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This sequence is a variant of A307720 where we don't allow consecutive equal products of contiguous pairs.
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LINKS
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EXAMPLE
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The first terms, alongside a(n)*a(n+1), are:
n a(n) a(n)*a(n+1)
-- ---- -----------
1 1 1
2 1 2
3 2 4
4 2 2
5 1 3
6 3 6
7 2 4
8 2 6
9 3 3
10 1 4
11 4 8
12 2 4
13 2 6
14 3 3
15 1 5
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PROG
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(PARI) See Links section.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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