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A067383
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Numbers n such that sigma(phi(n))/sigma(n) = 3.
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7
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181, 899, 2501, 4687, 10991, 12989, 17653, 25199, 25853, 26549, 26657, 54473, 65941, 68381, 72007, 82777, 96197, 98903, 102719, 116449, 124013, 135907, 150121, 169153, 188917, 193553, 201173, 207461, 219559, 234301, 237961, 239279
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Donovan Johnson, Table of n, a(n) for n = 1..1000
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MATHEMATICA
| For[ n=1, True, n++, If[ DivisorSigma[ 1, EulerPhi[ n ] ]/DivisorSigma[ 1, n ]==3, Print[ n ] ] ]
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CROSSREFS
| Cf. A033631, A066831, A067382, A067384, A067385, A197952.
Sequence in context: A142552 A154628 A142731 * A107255 A163442 A137530
Adjacent sequences: A067380 A067381 A067382 * A067384 A067385 A067386
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KEYWORD
| nonn
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AUTHOR
| Dean Hickerson (dean.hickerson(AT)yahoo.com), Jan 20 2002
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