## Exercise: Fibonacci Sequence

The Fibonacci sequence *F(n)* can be defined by:

- F(0) = 0
- F(1) = 1
- F(n) = F(n-1) + F(n-2) for n >= 2

### Part 1: Compute the sequence

Create a program which prompts the user for a value for n and also asks whether the user wants to have all numbers up to the nth displayed or just the nth in isolation.

### Part 2: Golden ratio

The Golden Ratio is the limit of the ratio F(n) / F(n-1) as n tends to infinity. Amend your program to display also the value(s) of this ratio either at each step or at the final step accordingly.

### Bonus points

Amend the program so that it can calculate members of the sequence
where F(n) > 10^{10}.

Solutions: Fortran.