The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A069781

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A069781

Numbers k such that gcd(d(k^3), d(k)) is not a power of 2.
(history; published version)

#29 by Charles R Greathouse IV at Thu Sep 08 08:45:05 EDT 2022

PROG

(MAGMAMagma) f:=func<n| Gcd(#Divisors(n^3), #Divisors(n))>; [k:k in [1..14000]| not IsIntegral(Log(2, f(k)))]; // Marius A. Burtea, Oct 18 2019

Discussion

Thu Sep 08

08:45

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

#28 by Susanna Cuyler at Fri Oct 18 21:23:38 EDT 2019

STATUS

proposed

approved

#27 by Marius A. Burtea at Fri Oct 18 07:05:09 EDT 2019

STATUS

editing

proposed

#26 by Marius A. Burtea at Fri Oct 18 07:04:47 EDT 2019

COMMENTS

The numbers of the form 4 * 3^(7m 7*m - 1), m >= 1, are terms. - Marius A. Burtea, Oct 18 2019

#25 by Marius A. Burtea at Fri Oct 18 07:03:18 EDT 2019

COMMENTS

The numbers of the form 4 * 3^(7m - 1), m >= 1, are terms. - Marius A. Burtea, Oct 18 2019

STATUS

proposed

editing

#24 by Marius A. Burtea at Fri Oct 18 06:17:13 EDT 2019

STATUS

editing

proposed

#23 by Marius A. Burtea at Fri Oct 18 06:17:03 EDT 2019

PROG

(MAGMA) f:=func<n| Gcd(#Divisors(n^3), #Divisors(n))>; [k:k in [1..14000]| not IsIntegral(Log(2, f(k)))]; // Marius A. Burtea, Oct 18 2019

STATUS

proposed

editing

#22 by Michel Marcus at Fri Oct 18 01:14:05 EDT 2019

STATUS

editing

proposed

#21 by Michel Marcus at Fri Oct 18 01:14:02 EDT 2019

EXAMPLE

For n<100000,GCD gcd[d(n^3),d[n]] = {5,7,10,14,20,28,40,80} which is obtained for n={20736,576,432,2880,54000,20160,2160,15120} respectively.

STATUS

proposed

editing

#20 by Jon E. Schoenfield at Fri Oct 18 00:45:31 EDT 2019

STATUS

editing

proposed