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Search: id:A068078
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| A068078 |
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Numbers n such that (sigma(n)+sigma(n+1))/n is an integer. |
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+0
3
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| 1, 10, 34, 136, 169, 2402, 5329, 21004, 38184, 41164, 54722, 458010, 776112, 1060802, 5026562, 10800112, 11108164, 14366402, 65676408, 87026656, 102944992, 387999360, 1488668112, 4414086384, 10499710072, 28645019964
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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For the values listed here, the quotient is 3 or 4. Do larger quotients occur?
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MATHEMATICA
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For[n=1, True, n++, If[Mod[DivisorSigma[1, n]+DivisorSigma[1, n+1], n]==0, Print[n]]]
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CROSSREFS
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Cf. A067806, A068077.
Sequence in context: A119229 A119227 A166066 this_sequence A067806 A001446 A001890
Adjacent sequences: A068075 A068076 A068077 this_sequence A068079 A068080 A068081
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KEYWORD
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nonn
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AUTHOR
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Dean Hickerson (dean.hickerson(AT)yahoo.com), Feb 16 2002
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EXTENSIONS
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a(22)-a(26) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jan 31 2009
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