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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
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2, 2, 6, 8, 26, 21, 110, 128, 342, 410, 1862, 1365, 7562, 7022, 17477, 32768, 123362, 87381, 496694, 419430, 1198373, 1906502, 8023886, 5592405, 26843546, 30973322, 89478486, 115043767, 518358122, 286331153, 2078209982, 2147483648, 5206020966, 8084644322
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 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
| 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
| 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
| Sequence in context: A052957 A197465 A157253 * A003178 A079494 A169970
Adjacent sequences: A074930 A074931 A074932 * A074934 A074935 A074936
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KEYWORD
| nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Oct 04 2002
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EXTENSIONS
| a(16)-a(34) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Nov 03 2011
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