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# OeisWiki:Community Portal

## Contents

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.

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## Sequence of the Day for October 19

A065918: Logarithm of
 2 + 2√  3
.
1.3169578969248...
This number figures in the search for Mersenne primes thus: the Mersenne number
 M = 2 n  −  1
is prime if and only if
 M
divides

cosh (2n  − 2 log (2 +
2  3
))
=
 e  + { 2 n  − 2 log (2 + 2√  3 ) } + e  − { 2 n  − 2 log (2 + 2√  3 ) } 2
=
 (2 + 2√  3 )  + { 2 n  − 2  } + (2 + 2√  3 )  − { 2 n  − 2  } 2
,

where
 cosh (x)
is the hyperbolic cosine function. David Wilson has proposed calling the number
 log (2 + 2√  3 )
the Helms constant.
The number
2 +
2  3
= tan
 5 π 12
= cot
 π 12
is sometimes called the Kasner constant (see A019973 for decimal expansion).