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Search: id:A115855
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| A115855 |
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Number of partitions of 1 into fractions i/j with 1<=i<j<=n and i,j coprime. |
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+0
4
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| 0, 1, 3, 6, 12, 21, 35, 58, 106, 188, 243, 493, 593, 1062, 3275, 5507, 5803, 12426, 12915, 42410
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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A115856(n) = a(n+1) - a(n).
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EXAMPLE
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a(4) = #{1/2+1/2, 1/2+1/4+1/4, 1/3+2/3, 1/3+1/3+1/3, 1/4+3/4,
1/4+1/4+1/4+1/4} = 6.
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CROSSREFS
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Cf. A002966, A000041, A000010.
Cf. A116084, A038566, A038567.
Sequence in context: A084439 A034344 A054578 this_sequence A128128 A006330 A087503
Adjacent sequences: A115852 A115853 A115854 this_sequence A115856 A115857 A115858
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 01 2006
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