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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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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
(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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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: A053222 A129646 A058036 this_sequence A090559 A126761 A098570
Adjacent sequences: A136176 A136177 A136178 this_sequence A136180 A136181 A136182
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KEYWORD
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more,nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Dec 19 2007
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