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 December 1

A188892: Numbers \scriptstyle n \, such that there is no triangular \scriptstyle n \,-gonal number greater than 1.

{ 11, 18, 38, 102, 198, 326, 486, ... }

The triangular numbers are essentially the building blocks of the other figurate numbers. Therefore it is rather surprising that there can be sequences of \scriptstyle n \,-gonal numbers that don't overlap with the sequence of triangular numbers at all (other than 0 and 1.) T. D. Noe has demonstrated that the equation \scriptstyle x^2 + x \,=\, (n - 2)y^2 - (n - 4)y \, has no integer solutions \scriptstyle x \,\geq\, y \,>\, 1 \,, as conversion to a generalized Pell equation shows that if \scriptstyle n \,=\, k^2 + 2 \,, then the first equation has only a finite number of solutions. From there one can pinpoint those values of \scriptstyle n \, that produce no integer solutions greater than 1.

Personal tools