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?
For e.g. any range of number 0  n
to:
Is there a name for this kind of formula or calculation? 


The tent map. In your case it'd be scaled to $f(x) = 2 \min(x, 6x)$. 

