Hi, Narbe,
the question defines by induction a sequence of integers in
:
and, for
,
. So
:
. And so on. The question is: give an expression for
for all
.
My advice would be to compute a few terms of the sequence and look at what happens.
The "pseudo-random numbers" thing is a reference to a well-known method of getting random numbers (or kind of) on a computer, that works with similar inductive equations (but with larger numbers than 4 and 7). To learn more (not for your exercise but personal interest), look at
this.