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Search: id:A066171
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| A066171 |
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Numbers n such that d(n) = EulerPhi(n+1) - EulerPhi(n), where d(n) denotes the number of divisors of n. |
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+0
1
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| 6, 74, 315, 344, 5313, 17534, 23655, 27027, 46035, 54494, 56865, 139814
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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These are the n at which EulerPhi(n) is increasing at a rate equal to d(n).
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EXAMPLE
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d(74) = 4 = 40 - 36 = EulerPhi(75) - EulerPhi(74).
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MATHEMATICA
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Select[ Range[ 1, 10^6 ], EulerPhi[ # + 1 ] - EulerPhi[ # ] == DivisorSigma[ 0, # ] & ]
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CROSSREFS
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Adjacent sequences: A066168 A066169 A066170 this_sequence A066172 A066173 A066174
Sequence in context: A089926 A135594 A058793 this_sequence A057783 A069852 A049235
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Dec 14 2001
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