# Talk:Centered hexagonal number

WikiProject Mathematics (Rated Start-class, Low-priority)
This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of Mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Mathematics rating:
 Start Class
 Low Priority
Field:  Number theory

The difference between (2n)2 and the nth centered hexagonal number is a number of the form 3n2 + 3n − 1, - is this statement correct?--Booradleyp (talk) 11:22, 31 December 2011 (UTC)

## Testing / finding the root

This formula will work to find the root of a centred hexagonal number, would it be useful to add to the article?

${\displaystyle n={\frac {1}{2}}\left({{\sqrt {8\times {\frac {x-1}{6}}+1}}+1}\right)}$

Where x is the hexagonal number and n is the root to be found. Dobz116 (talk) 11:25, 29 August 2011 (UTC)

Agree its useful to add a method of calculating the root, I added this before seeing the talk page, using the following formula:

${\displaystyle n={{3+{\sqrt {9-12(1-x)}}} \over 6}}$

which has fewer operations than the example you've given Ideasman42 (talk) 04:06, 13 August 2017 (UTC)