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A364976
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3-abundant numbers k such that k/(sigma(k)-3*k) is an integer.
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2
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180, 240, 360, 420, 540, 600, 780, 1080, 1344, 1872, 1890, 2016, 2184, 2352, 2376, 2688, 3192, 3276, 3744, 4284, 4320, 4680, 5292, 5376, 5796, 6048, 6552, 7128, 7440, 8190, 10416, 13776, 14850, 18600, 19824, 19872, 20496, 21528, 22932, 25056, 26208, 26496, 26784
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OFFSET
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1,1
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COMMENTS
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Numbers k such that the sum of the divisors of k except for one of them is equal to 3*k.
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LINKS
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EXAMPLE
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180 is a term since sigma(180) - 3*180 = 6 > 0 and 180 is divisible by 6.
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MATHEMATICA
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Select[Range[27000], (d = DivisorSigma[1, #] - 3*#) > 0 && Divisible[#, d] &]
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PROG
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(PARI) is(n) = {my(d = sigma(n) - 3*n); d > 0 && n%d == 0; }
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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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