Simplest way to solve n in a series in which $n = 4\%$ of $ n-1$ I'm trying to figure out the best way to approach this simple problem.
I have a series of numbers in which $n =4%$ of $n-1$ 
basically giving  $100~4~0.16~0.0064~...$
The function should take three inputs 
1) the initial number $(100)$
2) the percentage $(4\%) $
3) and $n$ and return the value 
for example  looking at the numbers above if $n=2$ it should return $ 0.16$
I guess I could just use a loop but isn't there a more elegant way?

So if $a_0\in\mathbb R$ is your initial value and $a_n=0.04\cdot a_{n-1}$ for $n\geq 1$, i.e. $a_n$ is $4\%$ of the previous number $a_{n-1}$, then
$$
a_n=0.04^n\cdot a_0,\quad n\geq 1.
$$
