The On-Line Encyclopedia of Integer Sequences (OEIS)

The OEIS is supported by the many generous donors to the OEIS Foundation.

Revision History for A020488

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

A020488

Numbers n such that tau(n) (or sigma_0(n)) = phi(n).
(history; published version)

#57 by Alois P. Heinz at Sat Sep 24 13:43:09 EDT 2022

STATUS

proposed

approved

#56 by Michel Marcus at Sat Sep 24 13:33:43 EDT 2022

STATUS

editing

proposed

#55 by Michel Marcus at Sat Sep 24 13:33:34 EDT 2022

LINKS

A. P. Minin, <a href="http://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=sm&paperid=7282&option_lang=eng">"On integers N such that the number of divisors of N equals the number of integers less than N and prime to it"</a> , Math. Soc. Moscow, Vol. 17, (1894), pp. 537-544 (some front matter is in English and German, article is in Russian)

STATUS

approved

editing

#54 by Charles R Greathouse IV at Thu Sep 08 08:44:45 EDT 2022

PROG

(MAGMAMagma) [n: n in [1..1000] | EulerPhi(n) eq NumberOfDivisors(n)]; // Marius A. Burtea, Dec 20 2018

Discussion

Thu Sep 08

08:44

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

#53 by Susanna Cuyler at Tue Dec 24 21:40:58 EST 2019

STATUS

proposed

approved

#52 by Jon E. Schoenfield at Tue Dec 24 20:14:30 EST 2019

STATUS

editing

proposed

#51 by Jon E. Schoenfield at Tue Dec 24 20:14:27 EST 2019

REFERENCES

G. Polya Pólya and G. Szego, Szegő, Problems and Theorems in Analysis II, Springer, 1976, Part VIII, Problem 45.

STATUS

approved

editing

#50 by Peter Luschny at Wed Feb 06 13:13:00 EST 2019

STATUS

reviewed

approved

#49 by Joerg Arndt at Sat Feb 02 12:00:38 EST 2019

STATUS

proposed

reviewed

#48 by Alonso del Arte at Sat Feb 02 11:51:01 EST 2019

STATUS

editing

proposed