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Search: id:A047630
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| A047630 |
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Numbers n such that n | Sigma(n) * Phi(n) and n not congruent to 0 (mod 6). |
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+0
1
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| 1, 28, 40, 117, 135, 196, 200, 224, 496, 640, 775, 819, 891, 1000, 1372, 1521, 1550, 1568, 1701, 1792, 2176, 2325, 2480, 3100, 3159, 3200, 3375, 3724, 4455, 5000, 5632, 5733, 6200, 6860, 6875, 6975, 8128, 9604, 10240, 10880, 10935, 10976, 11907
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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George E. Andrews, "Number Theory," Dover Books, NY, 1971, Page 84.
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MATHEMATICA
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Do[ If[ Mod[ n, 6 ]!=0, If[ Mod[ DivisorSigma[ 1, n ]*EulerPhi[ n ], n ]==0, Print[ n ] ] ], {n, 1, 25000} ]
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CROSSREFS
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Cf. A011775.
Sequence in context: A034964 A109798 A084807 this_sequence A135789 A025368 A025359
Adjacent sequences: A047627 A047628 A047629 this_sequence A047631 A047632 A047633
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KEYWORD
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easy,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 22 2000
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