The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A086892 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A086892

Greatest common divisor of 2^n-1 and 3^n-1.
(history; published version)

#31 by Charles R Greathouse IV at Thu Sep 08 08:45:11 EDT 2022

PROG

(MAGMAMagma) [Gcd(2^n-1, 3^n-1): n in [1..75]]; // Vincenzo Librandi, Sep 02 2015

Discussion

Thu Sep 08

08:45

OEIS Server: https://oeis.org/edit/global/2944

#30 by Jon E. Schoenfield at Sun Jan 16 23:02:56 EST 2022

STATUS

editing

approved

#29 by Jon E. Schoenfield at Sun Jan 16 23:02:54 EST 2022

COMMENTS

a(n) is a simple (the simplest?) example of a divisibility sequence associated to a rational point on an algebraic group of dimension larger than two. Specifically, it is the divisibility sequence associated to the point (2,3) on the two -dimensional torus G_m^2. Ailon and Rudnick conjecture that a(n) = 1 for infinitely many n.

STATUS

approved

editing

#28 by Charles R Greathouse IV at Fri Nov 13 15:37:19 EST 2015

STATUS

editing

approved

#27 by Charles R Greathouse IV at Fri Nov 13 15:37:15 EST 2015

LINKS

<a href="/index/Di#divseq">Index to divisibility sequences</a>

STATUS

approved

editing

#26 by Joerg Arndt at Wed Sep 02 03:28:06 EDT 2015

STATUS

proposed

approved

#25 by Robert Israel at Wed Sep 02 01:37:45 EDT 2015

STATUS

editing

proposed

#24 by Robert Israel at Wed Sep 02 01:37:23 EDT 2015

MAPLE

seq(igcd(2^n-1, 3^n-1), n=1..100); # Robert Israel, Sep 02 2015

STATUS

proposed

editing

#23 by Michel Marcus at Wed Sep 02 01:14:41 EDT 2015

STATUS

editing

proposed

#22 by Michel Marcus at Wed Sep 02 01:14:35 EDT 2015

EXTENSIONS

Replaced arXiv URL by with non-cached version - _by _R. J. Mathar_, Oct 23 2009