Hey Guys!

I am hoping to create my own 14 day ATR. 

I have the average true range calculation down, the only I am stumped on is calculating a Wilder's or Exponential Smoothing Factor. Would much appreciate some help.

Smoothing Factor formula is: 

(a*TR[0])+(1-a)*ATR[1] 

where a is (2/(n+1)) or 1/n