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A065818
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3*phi(n) = 2*sigma(n).
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4
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5, 119, 3553, 4147, 8323, 198679, 218569, 248501, 298129, 468809, 547261, 1098349, 1398061, 1947379, 1990417, 3076549, 3453289, 3994753, 6969529, 7690249, 8790439, 11905457, 13097327, 14346577, 14732011, 14988967, 15286973, 16145269
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Harry J. Smith, Table of n, a(n) for n = 1..75
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EXAMPLE
| n = 3553, 3*phi(3553) = 8640 = 2*4320 = 2*sigma(3553)
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MATHEMATICA
| Select[Range[20000000], 3EulerPhi[#]==2DivisorSigma[1, #]&] (* From Harvey P. Dale, Apr 18 2011 *)
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PROG
| (PARI) { n=0; for (m=1, 10^9, if (3*eulerphi(m) == 2*sigma(m), write("b065818.txt", n++, " ", m); if (n==75, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 31 2009]
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CROSSREFS
| Cf. A000010, A000203, A062699, A065819.
Sequence in context: A144998 A067359 A156962 * A139189 A155202 A168599
Adjacent sequences: A065815 A065816 A065817 * A065819 A065820 A065821
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Nov 23 2001
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EXTENSIONS
| Terms a(22) - a(28) from Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 31 2009
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