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Search: id:A136179
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| A136179 |
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a(n) = product{k=1 to d(n)-1) GCD(b(k),b(k+1)), where b(k) is the kth positive divisor of n and d(n) = the number of positive divisors of n. |
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+0
4
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| 1, 1, 1, 2, 1, 3, 1, 8, 3, 5, 1, 12, 1, 7, 5, 64, 1, 81, 1, 100, 7, 11, 1, 192, 5, 13, 27, 196, 1, 150, 1, 1024, 11, 17, 7, 1944, 1, 19, 13, 800, 1, 3087, 1, 484, 45, 23, 1, 12288, 7, 625, 17, 676, 1, 19683, 11, 1568, 19, 29, 1, 18000, 1, 31, 63, 32768, 13, 11979, 1, 1156, 23
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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a(n) = the product of the terms in row n of A136178.
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LINKS
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Diana Mecum, Table of n, a(n) for n=1,...,796
Leroy Quet, Home Page (listed in lieu of email address)
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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 a(20) = 1*2*1*5*10 = 100.
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CROSSREFS
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Cf. A136178, A136180, A136182.
Sequence in context: A165401 A140966 A058036 this_sequence A126761 A090559 A098570
Adjacent sequences: A136176 A136177 A136178 this_sequence A136180 A136181 A136182
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Dec 19 2007
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EXTENSIONS
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Added terms a(26) - a(796). - Diana Mecum (diana.mecum(AT)gmail.com), Dec 29 2008
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