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Search: id:A088722
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| A088722 |
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Number of divisors d>1 of n such that also d+1 divides n. |
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+0
6
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| 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 4, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 3, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 0, 1, 0, 0, 0
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OFFSET
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1,12
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COMMENT
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a(A088723(n))>0, a(A088724(n))=1, a(A088725(n))=0;
a(A088726(n))=n, a(k)<>n, for n<A088726(n).
a(2n+1) = 0. - Chandler
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EXAMPLE
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n=144: divisors(144)={1,2,3,4,6,8,9,12,16,18,24,36,48,72,144}, there are a(144)=3 divisors d>1 such that also d+1 divides 144: (2,3), (3,4) and (8,9).
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CROSSREFS
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Cf. A088723, A088724, A088725, A088726.
Sequence in context: A082786 A101638 A070141 this_sequence A122180 A033772 A086015
Adjacent sequences: A088719 A088720 A088721 this_sequence A088723 A088724 A088725
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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), Oct 12 2003
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), May 29 2008
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