A074934 Number of integers in {1, 2, ..., Fibonacci(n)} that are coprime to n.

1, 1, 2, 2, 4, 3, 12, 11, 23, 22, 81, 48, 216, 162, 325, 494, 1504, 861, 3961, 2706, 6256, 8051, 27412, 15456, 60020, 56028, 130946, 136205, 496497, 221878, 1302841, 1089155, 2136108, 2683712, 6327404, 4976784, 23504904, 18515449, 38920607, 40933662, 161541601

Offset

1,3

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..41.

Example

There are four integers in {1, 2, ..., Fibonacci(5) = 5} that are coprime to 5, i.e. 1, 2, 3, 4. Hence a(5) = 4.

Mathematica

h[n_] := Module[{l}, l = {}; For[i = 1, i <= Fibonacci[n], i++, If[GCD[i, n] == 1, l = Append[l, i]]]; l]; Table[Length[h[i]], {i, 1, 21}]
Table[Count[Range[Fibonacci[n]], _?(CoprimeQ[#, n]&)], {n, 25}] (* Harvey P. Dale, Oct 31 2011 *)

Crossrefs

Sequence in context: A241580 A323257 A054529 * A089886 A324648 A071511

Adjacent sequences: A074931 A074932 A074933 * A074935 A074936 A074937

Keyword

nonn

Author

Joseph L. Pe, Oct 04 2002

Extensions

More terms from Harvey P. Dale, Oct. 31 2011

a(26)-a(41) from Donovan Johnson, Nov 03 2011

Status

approved