The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A126260 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A126260

Irregular triangle read by rows where row n contains the positive integers k, k<=n, where every positive integer <=k and coprime to k is also coprime to n.
(history; published version)

#13 by Ray Chandler at Thu Oct 10 13:55:16 EDT 2019

STATUS

editing

approved

#12 by Ray Chandler at Thu Oct 10 13:55:13 EDT 2019

MATHEMATICA

f[n_] := Select[Range[n], GCD[ #, n] == 1 &]; g[n_] := Select[Range[n], Times @@ GCD[f[ # ], n] == 1 &]; Flatten@Table[g[n], {n, 17}] (* _Ray Chandler_, Dec 24 2006 *)

STATUS

approved

editing

#11 by N. J. A. Sloane at Mon Aug 21 22:37:21 EDT 2017

STATUS

proposed

approved

#10 by Michael De Vlieger at Mon Aug 21 22:34:52 EDT 2017

STATUS

editing

proposed

#9 by Michael De Vlieger at Mon Aug 21 22:34:46 EDT 2017

LINKS

Michael De Vlieger, <a href="/A126260/b126260.txt">Table of n, a(n) for n = 1..12325</a> (rows 1 <= n <= 300).

MATHEMATICA

Table[Select[Range@ n, Function[k, AllTrue[Select[Range@ k, CoprimeQ[#, k] &], CoprimeQ[#, n] &]]], {n, 17}] // Flatten (* Michael De Vlieger, Aug 21 2017 *)

STATUS

approved

editing

#8 by Charles R Greathouse IV at Wed Apr 09 10:16:59 EDT 2014

AUTHOR

Leroy Quet , Dec 22 2006

Discussion

Wed Apr 09

10:16

OEIS Server: https://oeis.org/edit/global/2156

#7 by N. J. A. Sloane at Wed Feb 05 20:18:30 EST 2014

AUTHOR

_Leroy Quet _ Dec 22 2006

Discussion

Wed Feb 05

20:18

OEIS Server: https://oeis.org/edit/global/2118

#6 by Russ Cox at Fri Mar 30 17:29:54 EDT 2012

EXTENSIONS

Extended by _Ray Chandler (rayjchandler(AT)sbcglobal.net), _, Dec 24 2006

Discussion

Fri Mar 30

17:29

OEIS Server: https://oeis.org/edit/global/154

#5 by N. J. A. Sloane at Sat Oct 02 03:00:00 EDT 2010

LINKS

Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> (listed in lieu of email address)

KEYWORD

nonn,tabf,new

#4 by N. J. A. Sloane at Fri Jan 09 03:00:00 EST 2009

LINKS

Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> (listed in lieu of email address)

KEYWORD

nonn,tabf,new

AUTHOR

Leroy Quet (qq-quet(AT)mindspring.com), Dec 22 2006