Changes

*The notation <math>^n a</math>  means <math> a^a^\cdots^a</math> the application of exponentiation <math> n-1</math> times.

*The notation <math>^n a</math>  means <math> a^a^\cdots^a</math> the application of exponentiation <math> n-1</math> times.

*For any positive real a>0 and non-negative integer <math>n\ge 0</math> we define <math>^n a</math>by:

*For any positive real a>0 and non-negative integer <math>n\ge 0</math> we define <math>^n a</math>by:

<math>^n a</math> = \begin{cases}  

<math>^n a = \begin{cases}  

1,  & \mbox{if }n\mbox{=0} \\

1,  & \mbox{if }n\mbox{=0} \\

a^{[(n-1)a]}, & \mbox{if }n\mbox{ >0}  

a^{[(n-1)a]}, & \mbox{if }n\mbox{ >0}  

\end{cases}</math>

\end{cases}</math>