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.
Create a function that determines the number of pairs of mature rabbits after n months, beginning with one **immature
** pair of these idealized rabbits that produce b pairs of offspring at the end of each month.
To illustrate the problem, consider the following example:
n = 5 months
b = 3 births
-> 19 mature rabbit pairs
| Month | Immature pairs | Mature pairs |
|---|---|---|
| 0 | 1 | 0 |
| 1 | 0 | 1 |
| 2 | 3 | 1 |
| 3 | 3 | 4 |
| 4 | 12 | 7 |
| 5 | 21 | 19 |
Any Fibonacci number can be computed using the following equation: F(n) = F(n-1) + F(n-2)