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Search: id:A063893
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| A063893 |
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Numbers n such that sum of proper divisors or aliquot parts of n^2 is a square. |
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1
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OFFSET
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1,2
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 10.
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EXAMPLE
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a(3)=49 because 49^2=2401 and sum of aliquot divisors of 2401: 1+7+49+343=400=20^2.
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PROGRAM
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(PARI) s(n)=sigma(n)-n; for(n=1, 10^8, if(issquare(s(n^2)), print(n)))
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CROSSREFS
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Cf. A008847, A001065.
Sequence in context: A012100 A106842 A086459 this_sequence A145572 A034201 A099346
Adjacent sequences: A063890 A063891 A063892 this_sequence A063894 A063895 A063896
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KEYWORD
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hard,nice,nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Aug 29 2001
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EXTENSIONS
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One more term from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Jun 06 2002
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