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Search: id:A097645
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| A097645 |
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Numbers n such that n=sigma(phi(n)+pi(n)). |
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+0
3
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| 1, 6, 54, 78, 1296, 1482, 6480, 6552, 14040, 20160, 36936, 1273896
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OFFSET
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1,2
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COMMENT
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Has this sequence odd terms greater than 1? There is no other term up to 3*10^7.
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EXAMPLE
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1273896 is in the sequence because pi(1273896)=98190,
phi(1273896)=391680 and sigma(98190+391680)=1273896.
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MATHEMATICA
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Do[If[n==DivisorSigma[1, EulerPhi[n]+PrimePi[n]], Print[n]], {n, 10000000}]
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CROSSREFS
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Cf. A097646, A018784.
Sequence in context: A066357 A109092 A068416 this_sequence A072368 A116138 A060774
Adjacent sequences: A097642 A097643 A097644 this_sequence A097646 A097647 A097648
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KEYWORD
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more,nonn
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AUTHOR
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Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Sep 07 2004
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