# Recursion 3

**Computer Science**Level 2

Let \( a_{0}=0 \), \( a_{1}=1 \) and \( a_{n}= n^{a_{n-1}}\) where \(n\ge2\) be a recursive function. Write a program that calculates the image value of any non-negative integer n.

Can you find **\( a_{4}\) mod \(2015\) mod \(20\) mod \(15+2000\)** ?