For e.g. any range of number 0 - n



> 
> 0 1 2 3 4 5 6 
> 
> 
> 


to: 



> 
> 0 2 4 6 4 2 0 
> 
> 
> 


Is there a name for this kind of formula or calculation?



Is there a name for a formula to calculate ascending numbers to a quadratic-like sequence?
The [tent map](http://en.wikipedia.org/wiki/Tent_map). In your case it'd be scaled to $f(x) = 2 \min(x, 6-x)$.


