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Search: id:A060667
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| A060667 |
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phi(x) = n has exactly 4 solutions. |
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+0
2
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| 4, 6, 18, 42, 100, 162, 184, 208, 328, 424, 460, 468, 486, 492, 616, 636, 664, 688, 700, 712, 784, 820, 900, 904, 1020, 1060, 1072, 1168, 1240, 1264, 1276, 1288, 1300, 1356, 1360, 1384, 1404, 1458, 1480, 1528, 1672, 1740, 1768, 1864, 1896, 1900, 1908, 2008
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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EXAMPLE
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18 = phi(19) = phi(27) = phi(38) = phi(54).
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MATHEMATICA
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a = Table[ 0, {2500} ]; Do[ p = EulerPhi[ n ]; If[ p < 2501, a[ [ p ] ]++ ], {n, 1, 5000} ]; Select[ Range[ 2500 ], a[ [ # ] ] == 4 & ]
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CROSSREFS
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Cf. A007366, A007367.
Sequence in context: A107390 A051253 A064403 this_sequence A005959 A057393 A012928
Adjacent sequences: A060664 A060665 A060666 this_sequence A060668 A060669 A060670
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 18 2001
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