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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 October 15

A011371:
n
minus its binary weight,
n   ≥   0
.
{ 0, 0, 1, 1, 3, 3, 4, 4, 7, 7, ... }
This is also the exponent of the highest power of 2 dividing
n!
⌊  log2(n) ⌋
i   = 1
  
n
2i
.
This sequence shows why, in binary, 0 and 1 are the only two numbers
n
such that
n
equals the sum of its digits raised to the consecutive powers. 1 raised to any consecutive power is still 1 and thus any sum of digits raised to consecutive powers for any
n > 1
falls short of equaling the value of
n
by the
n
-th number of this sequence.