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A066471
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Numbers n such that sigma(EulerPhi(sigma(n))) = sigma(n).
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1
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1, 2, 8, 12, 128, 240, 350, 366, 368, 575, 671, 720, 743, 1098, 2417, 6912, 18967, 19399, 32768, 142560, 173340, 179010, 184032, 188892, 203310, 209628, 225342, 228582, 232160, 244782, 255460, 271072, 274422, 279045, 282285, 287810, 304910
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,250
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MATHEMATICA
| Select[Range[1, 10^6], DivisorSigma[1, EulerPhi[DivisorSigma[1, # ]]] == DivisorSigma[1, # ] &]
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PROG
| (PARI) { n=0; for (m=1, 10^10, if (sigma(eulerphi(sigma(m))) == sigma(m), write("b066471.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Feb 17 2010]
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CROSSREFS
| Sequence in context: A013190 A176968 A126192 * A001229 A120000 A067678
Adjacent sequences: A066468 A066469 A066470 * A066472 A066473 A066474
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KEYWORD
| nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 02 2002
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