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Search: id:A074920
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| A074920 |
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phi(n) = 6n/Pi^2 rounded to nearest integer. |
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+0
1
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OFFSET
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1,2
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COMMENT
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The average value of phi(n) can be approximated for large n by 6n/Pi^2 (Tattersall, p. 162).
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REFERENCES
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Tattersall, J. "Elementary Number Theory in Nine Chapters", Cambridge University Press, 2001.
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EXAMPLE
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phi(99) = 60 and 6*99/Pi^2 = 60.1848...., which rounds off to 60. Hence 99 is a term of the sequence.
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MATHEMATICA
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s = Pi^2; l = {}; Do[ If[Abs[EulerPhi[n] - 6 n/ s] <= 0.5, l = Append[l, n]], {n, 1, 10^5}]; l
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CROSSREFS
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Sequence in context: A067242 A028354 A028355 this_sequence A102842 A009263 A084314
Adjacent sequences: A074917 A074918 A074919 this_sequence A074921 A074922 A074923
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 01 2002
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