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Search: id:A136178
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| A136178 |
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Irregular array read by rows: row n contains the GCDs of each pair of consecutive positive divisors of n. |
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+0
4
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| 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 2, 4, 1, 3, 1, 1, 5, 1, 1, 1, 1, 2, 6, 1, 1, 1, 7, 1, 1, 5, 1, 2, 4, 8, 1, 1, 1, 3, 3, 9, 1, 1, 2, 1, 5, 10
(list; table; graph; listen)
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OFFSET
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2,4
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COMMENT
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Each row has d(n)-1 terms, where d(n) is the number of positive divisors of n. The first row listed is row 2.
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EXAMPLE
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The positive divisors of 20 are 1,2,4,5,10,20. GCD(1,2)=1. GCD(2,4)=2. GCD(4,5)=1. GCD(5,10)=5. And GCD(10,20)=10. So row 20 is (1,2,1,5,10).
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CROSSREFS
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Cf. A136179, A136180, A136181.
Sequence in context: A101950 A104562 A111603 this_sequence A047140 A047150 A102054
Adjacent sequences: A136175 A136176 A136177 this_sequence A136179 A136180 A136181
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KEYWORD
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more,nonn,tabl
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Dec 19 2007
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