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Search: id:A087081
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| A087081 |
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Sum of the elements in the coprime subsets of the integers 1 to n. |
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+0
4
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| 0, 1, 6, 24, 48, 156, 192, 580, 836, 1444, 1660, 4596, 4980, 13184, 14768, 17308, 21756, 55888, 58768, 146416, 157552, 181008, 196304, 481664, 500096, 765648, 825152, 1073920, 1148288, 2745728, 2768768, 6505728, 7453952, 8233792, 8736960
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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A coprime set of integers has (m,n)=1 for each pair of integers in the set.
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REFERENCES
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Alan Sutcliffe, Divisors and Common Factors in Sets of Integers, awaiting publication.
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EXAMPLE
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a(4)=48 since the 12 coprime subsets of (1,2,3,4) are ( ) (1) (2) (3) (4) (1,2) (1,3) (1,4) (2,3) (3,4) (1,2,3) (1,3 4) and the sum of the elements is 48.
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CROSSREFS
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A087078 gives the sum of the elements in the primitive subsets. A084422 gives the number coprime subsets. A087080 gives the number of elements in coprime subsets.
Sequence in context: A120572 A000056 A083170 this_sequence A089973 A033581 A009943
Adjacent sequences: A087078 A087079 A087080 this_sequence A087082 A087083 A087084
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KEYWORD
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nonn
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AUTHOR
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Alan Sutcliffe (alansut(AT)ntlworld.com), Aug 12 2003
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