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Search: id:A065154
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| A065154 |
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Numbers for which Cototient-of-Totient < Totient-of-Cototient. |
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+0
2
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| 2, 6, 12, 15, 24, 30, 48, 51, 60, 66, 70, 78, 90, 96, 102, 105, 120, 130, 132, 138, 140, 150, 154, 156, 165, 170, 174, 180, 190, 192, 204, 210, 230, 234, 238, 240, 246, 255, 260, 264, 266, 270, 276, 280, 282, 290, 300, 308, 312, 315, 318, 330, 340, 345, 348
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,1000
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FORMULA
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A051953[A000010(m)] < A000010[A051953(m)]
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EXAMPLE
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m=78 Phi[78]=24, 78-Phi[78]=cototient[78]=54, cototient[24]=24-Phi[24]=24-8=16,Phi[54]=18 so 16<18,ans m=78 is here.
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MATHEMATICA
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Flatten[Position[Sign[Table[co[eu[w]]-eu[co[w]], {w, 1, 1000}]], -1]].
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PROGRAM
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(PARI) { n=0; for (m = 2, 10^9, t=eulerphi(m); c=m - t; if (t - eulerphi(t) < eulerphi(c), write("b065154.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Oct 13 2009]
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CROSSREFS
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A051953, A000010.
Sequence in context: A152301 A152389 A114103 this_sequence A143408 A088915 A084790
Adjacent sequences: A065151 A065152 A065153 this_sequence A065155 A065156 A065157
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Oct 19 2001
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