This site is supported by donations to The OEIS Foundation.

OeisWiki:Community Portal

From OeisWiki
Jump to: navigation, search

This page contains notes about the status of the OEIS wiki. It provides a brief description of the wiki setup. It will also be used to announce changes in the structure of the wiki, so it may be useful to add it to your watchlist by clicking on the watch tab at the top of the page.

Users can create and modify discussion pages here. The discussion pages are a reasonable place to make comments about the structure of the wiki.

Do not use the discussion pages to suggest changes to OEIS sequence entries.

An account is necessary to contribute to the Wiki. To request an account, click here. There was a time when the username was required to be your Real Name. This is no longer required, but is strongly recommended. If this evolving statement causes you to want to change your username, send email to David, and I can make the change.

A few preliminary pages (most of these need to be updated!)

Sequence of the Day for July 20

A007955: Product of divisors of
n, n   ≥   1
i  = 1
i ∣ n
i =
i  = 1
i [i ∣ n], n ≥ 1.

where [⋅] is the Iverson bracket.

{ 1, 2, 3, 8, 5, 36, 7, ... }
In Only Problems, Not Solutions!, Florentin Smarandache lists this sequence (page 24), describes it, and urges the reader to study it, saying nothing else. It is easy enough to see that each prime number
will occur once and only once in this sequence, namely, at
a (p)
. T. D. Noe goes much further than that and actually proves that each term of this sequence occurs just once. Of course not every positive integer occurs in this sequence (e.g., squares of primes). The product of divisors of
is sometimes called the divisorial of