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A109658
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Numbers k such that the sum of the digits of k^sigma(k) is divisible by k.
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0
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1, 2, 3, 9, 11, 18, 54, 74, 108, 135, 426, 531, 585, 1361, 3456, 6771, 7245, 7392, 11025, 11957, 21494, 27063, 41952, 68494, 72516, 108742, 128331
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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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The sum of the digits of 531^sigma(531) is 9558 and 9558 is divisible by 531, so 531 is in the sequence.
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MATHEMATICA
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Do[s = n^DivisorSigma[1, n]; k = Plus @@ IntegerDigits[s]; If[Mod[k, n] == 0, Print[n]], {n, 1, 10000}]
Select[Range[150000], Divisible[Total[IntegerDigits[#^DivisorSigma[ 1, #]]], #]&] (* Harvey P. Dale, Jul 19 2013 *)
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CROSSREFS
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KEYWORD
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base,nonn,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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