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A097023
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Numbers n such that the sum of the divisors of 2*n^2 is a square.
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7
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313, 335, 2612, 2817, 3015, 3820, 23508, 34380, 36647, 38193, 42217, 50281, 64972, 73535, 96404, 103180, 155991, 265364, 325847, 329823, 379953, 397068, 452529, 476545, 584748, 624748, 661815, 668660, 867636, 928620
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OFFSET
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1,1
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LINKS
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EXAMPLE
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sigma[2*313^2]=543^2
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MATHEMATICA
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Select[Range[950000], IntegerQ[Sqrt[DivisorSigma[1, 2#^2]]]&] (* Harvey P. Dale, Jul 10 2012 *)
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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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