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Search: id:A071707
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| A071707 |
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Numbers n such that n divides tau(n)*sigma(n). |
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+0
1
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| 1, 2, 6, 12, 18, 24, 28, 40, 84, 120, 224, 234, 240, 252, 360, 468, 496, 672, 864, 936, 1638, 1920, 2016, 2480, 3276, 4320, 4680, 6048, 6528, 6552, 7440, 8128, 9360, 10880, 22320, 22932, 26208, 30240, 32640, 32760, 47616, 56896, 58752
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OFFSET
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1,2
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EXAMPLE
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The divisors of 18 are {1,2,3,6,9,18}, so tau(18)=6 and sigma(18)=1+2+3+6+9+18=39, 18 is a term as 18*13=6*39=tau(18)*sigma(18).
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CROSSREFS
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Cf. A007691, A064840(n)=A000005(n)*A000203(n).
Sequence in context: A026229 A043343 A066080 this_sequence A069087 A085345 A032371
Adjacent sequences: A071704 A071705 A071706 this_sequence A071708 A071709 A071710
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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), Jun 03 2002
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