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A046754
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Numbers k such that the square of d(k) (number of divisors) divides k.
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7
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1, 9, 128, 625, 972, 1152, 2000, 2025, 5625, 6561, 7776, 8100, 10000, 10800, 18000, 21952, 26244, 30000, 32768, 35721, 50625, 55296, 56700, 64000, 64800, 65856, 70000, 80000, 84672, 89100, 90000, 97200, 98304, 99225, 105300, 109760, 110000
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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If k = 972, d(k) = sigma(0,k) = 18. Its square is 324 which divides 972.
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MATHEMATICA
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Select[Range[110000], IntegerQ[#/DivisorSigma[0, #]^2] &] (* Jayanta Basu, Jun 28 2013 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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