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Search: id:A074933
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| A074933 |
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Number of integers in {1, 2, ..., 2^n} that are coprime to n. |
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+0
1
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| 2, 2, 6, 8, 26, 21, 110, 128, 342, 410, 1862, 1365, 7562, 7022, 17477
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Compare the definition of a(n) to phi(n) = number of integers in {1, 2, ..., n} that are coprime to n.
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EXAMPLE
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The are six integers in {1, 2, ..., 2^3} that are coprime to 3, i.e. 1, 2, 4, 5, 7, 8. Hence a(3) = 6.
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MATHEMATICA
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h[n_] := Module[{l}, l = {}; For[i = 1, i <= 2^n, i++, If[GCD[i, n] == 1, l = Append[l, i]]]; l]; Table[Length[h[i]], {i, 1, 15}]
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CROSSREFS
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Sequence in context: A129383 A052957 A157253 this_sequence A003178 A079494 A131553
Adjacent sequences: A074930 A074931 A074932 this_sequence A074934 A074935 A074936
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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 04 2002
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