The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A057021 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A057021

Denominator of (sum of divisors of n / number of divisors of n).
(history; published version)

#39 by Charles R Greathouse IV at Thu Sep 08 08:45:01 EDT 2022

PROG

(MAGMAMagma) [Denominator(SumOfDivisors(n)/#Divisors(n)):n in [1..100]]; // Marius A. Burtea, Sep 08 2019

Discussion

Thu Sep 08

08:45

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

#38 by Michel Marcus at Fri Sep 20 06:19:21 EDT 2019

STATUS

reviewed

approved

#37 by Amiram Eldar at Fri Sep 20 05:33:39 EDT 2019

STATUS

proposed

reviewed

#36 by David A. Corneth at Thu Sep 19 15:40:04 EDT 2019

STATUS

editing

proposed

#35 by David A. Corneth at Thu Sep 19 15:39:59 EDT 2019

COMMENTS

a(n) = 2 when n is listed in A069081(n)) = 2. - Bernard Schott, Sep 19 2019

CROSSREFS

Cf. A000005, A000203, A009205, A054025, A057020 (numerator), A057022, A069081.

STATUS

proposed

editing

#34 by Bernard Schott at Thu Sep 19 15:24:49 EDT 2019

STATUS

editing

proposed

#33 by Bernard Schott at Thu Sep 19 15:23:46 EDT 2019

COMMENTS

a(n) = 2 when n is listed in A069081. - Bernard Schott, Sep 19 2019

STATUS

reviewed

editing

Discussion

Thu Sep 19

15:24

Bernard Schott: Put a(n) = 2 in comments.

#32 by Amiram Eldar at Thu Sep 19 15:17:59 EDT 2019

STATUS

proposed

reviewed

#31 by Bernard Schott at Thu Sep 19 08:00:17 EDT 2019

STATUS

editing

proposed

#30 by Bernard Schott at Thu Sep 19 07:59:12 EDT 2019

EXAMPLE

a(12)=3 since the 6 factors divisors of 12 are 1, 2, 3, 4, 6 and 12 and 1+2+3+4+6+12=28 and 28/6=14/3.

STATUS

proposed

editing

Discussion

Thu Sep 19

08:00

Bernard Schott: factors --> divisors in example.