login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A100826 a(1) = 1; a(n+1) = GCD(n,a(n))-th smallest positive integer not already in the sequence. 2
1, 2, 4, 3, 5, 10, 7, 14, 8, 6, 11, 22, 12, 9, 13, 15, 16, 17, 18, 19, 20, 21, 23, 46, 25, 50, 26, 24, 30, 27, 31, 62, 29, 28, 33, 32, 37, 74, 35, 34, 38, 36, 44, 39, 40, 47, 41, 42, 52, 43, 45, 51, 48, 49, 53, 54, 56, 55, 57, 58, 60, 59, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Probably a permutation of the positive integers.

This is a permutation iff, infinitely often, gcd(n, a(n)) = 1. Through n = 1000, gcd(n, a(n)) = 1 612 times, which is consistent with the natural conjecture that this is true with density 6/Pi^2 ~ 0.6079.... - Franklin T. Adams-Watters, Nov 28 2006

LINKS

Franklin T. Adams-Watters, Table of n, a(n) for n = 1..1000

MATHEMATICA

a[1] = 1; a[n_] := a[n] = Complement[ Range[250], Table[a[i], {i, n - 1}]][[GCD[n - 1, a[n - 1]]]]; Table[ a[n], {n, 60}] (* Robert G. Wilson v, Jan 10 2005 *)

CROSSREFS

Cf. A125628.

Sequence in context: A091449 A100834 A264996 * A232799 A276472 A245702

Adjacent sequences:  A100823 A100824 A100825 * A100827 A100828 A100829

KEYWORD

nonn

AUTHOR

Leroy Quet, Jan 06 2005

EXTENSIONS

More terms from Robert G. Wilson v, Jan 10 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 22 20:30 EST 2019. Contains 320404 sequences. (Running on oeis4.)