In his publication Liber Abaci Leonardo Bonacci, aka Fibonacci, posed a problem involving a population of idealized rabbits. These rabbits bred at a fixed rate, matured over the course of one month, had unlimited resources, and were immortal.
Beginning with one immature pair of these idealized rabbits that produce b pairs of offspring at the end of each month. Create a function that determines the number of pair of mature rabbits after n months.
To illustrate the problem, consider the following example:
```python
fib_rabbits(5, 3) returns 19
```
Month
Immature Pairs
Adult Pairs
0
1
0
1
0
1
2
3
1
3
3
4
4
12
7
5
21
19
Hint: any Fibonacci number can be computed using the following equation Fn = F(n-1) + F(n-2)
def fib_rabbits(end, factor):
    immatures, adults = 1, 0
    for month in range(end):
        immatures, adults = (factor * adults), (adults + immatures)
    return adults
def fib_rabbits(end, factor):
    immatures, adults = 1, 0
    for month in range(end):
        immatures, adults = (factor * adults), (adults + immatures)
    return adults