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A074933 Number of integers in {1, 2, ..., 2^n} that are coprime to n. 0
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; text; internal format)
OFFSET

1,1

COMMENTS

Compare the definition of a(n) to phi(n) = number of integers in {1, 2, ..., n} that are coprime to n.

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

There 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.

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}]

CROSSREFS

Sequence in context: A052957 A275441 A197465 * A157253 A003178 A079494

Adjacent sequences:  A074930 A074931 A074932 * A074934 A074935 A074936

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Oct 04 2002

EXTENSIONS

a(16)-a(34) from Donovan Johnson, Nov 03 2011

STATUS

approved

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Last modified May 30 00:10 EDT 2020. Contains 334710 sequences. (Running on oeis4.)