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Search: id:A007374
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| A007374 |
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Smallest k such that phi(x) = k has exactly n solutions.
(Formerly M1093)
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+0
11
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| 1, 2, 4, 8, 12, 32, 36, 40, 24, 48, 160, 396, 2268, 704, 312, 72, 336, 216, 936, 144, 624, 1056, 1760, 360, 2560, 384, 288, 1320, 3696, 240, 768, 9000, 432, 7128, 4200, 480, 576, 1296, 1200, 15936, 3312, 3072, 3240, 864, 3120, 7344, 3888, 720, 1680, 4992
(list; graph; listen)
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OFFSET
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2,2
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COMMENT
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Carmichael conjectured that no term exists for n=1.
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REFERENCES
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 840.
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LINKS
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T. D. Noe, Table of n, a(n) for n = 2..778
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, December 1972 [alternative scanned copy].
Eric Weisstein's World of Mathematics, Carmichael's conjecture
Eric Weisstein's World of Mathematics, Phi function.
Eric Weisstein's World of Mathematics, Carmichael's Totient Function Conjecture.
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MATHEMATICA
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a = Table[ 0, {10^5} ]; Do[ s = EulerPhi[ n ]; If[ s < 100001, a[ [ s ] ]++ ], {n, 1, 10^6} ]; Do[ k = 1; While[ a[ [ k ] ] != n, k++ ]; Print[ k ], {n, 2, 75} ]
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CROSSREFS
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Cf. A000010. Essentially same as A014573. Records in A105207, A105208. See also A097942.
Cf. A105207, A105208.
Sequence in context: A082906 A085083 A076745 this_sequence A105207 A133802 A076202
Adjacent sequences: A007371 A007372 A007373 this_sequence A007375 A007376 A007377
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KEYWORD
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nonn,easy,nice
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AUTHOR
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njas, Mira Bernstein, Robert G. Wilson v (rgwv(AT)rgwv.com)
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