Is there a name for a formula to calculate ascending numbers to a quadratic-like sequence?
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?
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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?