A120839 a(n) is the n-th positive integer which is coprime to the n-th Fibonacci number.

1, 2, 5, 5, 6, 11, 7, 13, 19, 13, 11, 35, 13, 15, 37, 26, 17, 39, 19, 43, 45, 22, 23, 85, 31, 26, 59, 46, 29, 87, 31, 58, 65, 34, 47, 125, 37, 39, 77, 101, 41, 95, 43, 67, 121, 46, 47, 179, 53, 68, 101, 77, 53, 125, 68, 109, 119, 58, 59, 263, 61, 62, 145, 115, 81, 133, 67

Offset

1,2

Links

Michael De Vlieger, Table of n, a(n) for n = 1..5000

Example

55 is the 10th Fibonacci number. 1,2,3,4,6,7,8,9,12,13,14,16,... is the sequence of positive integers which are coprime to 55. 13 is the 10th of these integers, so a(10)=13.

Mathematica

Table[Block[{m = Fibonacci@ n, r = {1}, k = 2}, While[Length@ r < n, If[GCD[k, m] == 1, AppendTo[r, k], Nothing]; k++]; Last@ r], {n, 67}] // Flatten (* Michael De Vlieger, Dec 26 2019 *)

Crossrefs

Diagonal of A129322.

Sequence in context: A145434 A220426 A117899 * A332525 A196608 A129228

Adjacent sequences: A120836 A120837 A120838 * A120840 A120841 A120842

Keyword

nonn

Author

Leroy Quet, Aug 18 2006

Extensions

Extended by Ray Chandler, Aug 22 2006

Status

approved