FSharp Program to print Fibonacci Series

open System

Console.Write("Enter the value of n:\t")
let number = Int32.Parse(Console.ReadLine())
Console.WriteLine("Enter the value of n:\t")
let mutable x = 0;
let mutable y = 1;       
Console.WriteLine(x);
Console.WriteLine(y);       
for i = 0 to number-2 do 
   let z = x + y       
   Console.WriteLine(z);
   x <- y
   y <- z 

Enter the value of n: 5
0
1
1
2
3