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A233553
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Amicable 5-tuples: (x1,...,x5) such that sigma(x1)=...=sigma(x5)=x1+...+x5. Groups of 5 subsequent terms list the five members in increasing size.
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13
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53542288800, 59509850400, 59999219280, 60074174160, 61695597600, 67154527440, 68763895200, 69626138400, 71957405520, 72598125600, 67509842400, 72747675000, 73605331800, 75710489400, 78953074200, 87113426400, 88410722400, 89398663200, 96058282320, 96369633360
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OFFSET
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1,1
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COMMENTS
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The 5-tuple starting with 53542288800 was given by Donovan Johnson. The common value of sigma(x) is 294821130240.
A larger 5-tuple, (55766707476480, 56992185169920, 57515254917120, 57754372515840, 57829096765440), was found by Michel Marcus on Dec 09 2013. The common value of sigma(x) is 285857616844800.
A still larger example (227491164588441600, 228507506351308800, 229862628701798400, 230878970464665600, 243752632794316800), probably the first one to be published, had been found by Yasutoshi Kohmoto in 2008, cf. link to SeqFan post.
There are different definitions for amicable k-tuples, cf. link to MathWorld.
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KEYWORD
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nonn,hard,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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