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Search: id:A146567
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| A146567 |
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Numbers n such that n*sigma_0(n)/(n+sigma_0(n))= c, c an integer. |
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3
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OFFSET
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1,1
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COMMENT
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A000027(n)*A000005(n)/(A000027(n)+A000005(n))=c, c an integer.
No other term < 5000000. [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 09 2008]
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MAPLE
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with(numtheory): a:=proc (n) if type(n*tau(n)/(n+tau(n)), integer) = true then n else end if end proc: seq(a(n), n=1..200000); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 09 2008]
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CROSSREFS
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Cf. A000027, A000005
Sequence in context: A137496 A051781 A077562 this_sequence A121119 A052565 A141900
Adjacent sequences: A146564 A146565 A146566 this_sequence A146568 A146569 A146570
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KEYWORD
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easy,nonn
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AUTHOR
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Ctibor O. Zizka (c.zizka(AT)email.cz), Nov 01 2008
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EXTENSIONS
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Corrected and extended (one term) by Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 09 2008
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