are all the terms of this chaotic map 0s?

Question

I'm trying to implement the algorithm proposed on this paper: A Simple Method for Image Encryption Using Chaotic Logistic Map but i cannot figure out the equation (7), i'm pretty sure that $X_0=0$, because is the sum of integer products (5) and (6). So, if that is the case, it means: the terms $X_1,X_2, X_3, X_4..$ of (1) are also 0, which make no sense to me. Is not supposed that the terms of the map (1) will be pseudo-random numbers?
I searched on other journals to check if it was a typo error, but is not the case. So the only thing that come to my mind is that i don't undertand the notation used in this paper. Thanks in advance.

Answer 1

Apparently the square brackets in $(5)$ and $(6)$ indicate division by $2^{40}$; compare $(6)$ and $(7)$ in this PDF. That reduces $X_{01}$ and $X_{02}$ to the range $(0,1)$, so that $(8)$ puts $X_0\in(0,1)$, where it should be.