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OeisWiki:Community Portal

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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 June 27

A002378: Pronic numbers
n 2 + n
... 1722, 1806, 1892, 1980, 2070, 2162, 2256, ...
The mathematician Augustus De Morgan was born on this date in 1806. When he turned 43 in 1849, he noticed that his age happened to be the square root of the year. The reason this was the case is that the year of his birth is a pronic number. These are numbers of the form
n 2 + n
, but they can also be expressed as
n 2n
(with a different offset, of course). Thus 1849 = 43 2, and 1806 = 43 2 – 43. People born in 1892 may have noticed a similar situation applied when they turned 44, but among those who are still with us today, people born in 1980 who are still alive in 2025 will then be able to say that their age is the square root of the year.
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