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A063831
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Sum of cubes of divisors is a square.
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0
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1, 2, 345, 690, 47196, 46248900, 53262468, 71315748, 140553735, 188194335, 215515727, 281107470, 288564647, 292978595, 310129096, 376388670, 431031454, 577129294, 585957190, 1474108335, 2133051720, 2489605188, 2948216670, 3270679304, 4043104611, 5142743032
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OFFSET
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1,2
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LINKS
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EXAMPLE
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345 is in the sequence since sigma_3(345) = 6552^2 is a square.
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MATHEMATICA
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Select[Range[10^5], IntegerQ[ Sqrt[ DivisorSigma[3, #] ] ] &] (* Amiram Eldar, Dec 06 2018 *)
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PROG
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(PARI) for(n=1, 10^5, if(issquare(sigma(n, 3)), print1(n, ", ")))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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