"An Exponential Function"

Given the following function:

What is the first 3 digits of the value of f(50)?

Once you understand the equation it's fairly trivial to write a script for this... remember to read the question carefully especially abdout the awnser it wants!

Awnser:

Source:

function solution(){
   $result = bcadd(bcpow(4, 50), bcpow(50, 3));
   $result = bcadd($result, bcpow(50, 2));
   $result = bcadd($result, 50);
   $result = bcsub($result, bcpow(2, 50));
   
   $result = bcdiv($result, bcpow(3, 50));
   echo $result[0].$result[1].$result[2];
}