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Search: id:A074891
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| A074891 |
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Numbers n such that sigma(n) = phi(3n). |
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+0
3
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| 15, 35, 357, 1045, 3339, 5049, 10659, 12441, 24871, 24969, 29029, 50065, 58435, 64285, 87685, 99693, 132957, 137885, 140335, 353133, 423657, 596037, 655707, 734517, 745503, 894387, 1390753, 1406427, 1529983, 1641783, 1739507, 1823877
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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sigma(15) = 24 = phi(3 * 15), so 15 is a term of the sequence.
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MATHEMATICA
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Select[ Range[1936556], EulerPhi[3# ] == DivisorSigma[1, # ] &]
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CROSSREFS
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Sequence in context: A037074 A107423 A027442 this_sequence A134509 A062712 A033709
Adjacent sequences: A074888 A074889 A074890 this_sequence A074892 A074893 A074894
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KEYWORD
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easy,nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Sep 13 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 17 2002
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