##### Report abuse Source:
```int Fibonacci(int n) //use long or double if n>46
{
if (n < 2) return n;
return Fibonacci(n - 1) + Fibonacci(n - 2);
}```
##### Sample Usage:
```using System;

namespace NullDoc
{
class Program
{
static void Main(string[] args)
{
int number = 100;
do
{
Console.Write("Please enter a valid number (1-47):");
} while (!((int.TryParse(Console.ReadLine(), out number) && number <= 47)));

Console.WriteLine("Fibonacci of {0} is {1}", number, Program.Fibonacci(number));
}

private static int Fibonacci(int n)
{
if (n < 2) return n;
return Fibonacci(n - 1) + Fibonacci(n - 2);
}
}
}
```

In mathematics, the Fibonacci numbers or Fibonacci series or Fibonacci sequence are the numbers in the following integer sequence:0, 1, 1, 2, 3, 5, 8, 13... By definition, the first two numbers in the Fibonacci sequence are 0 and 1, and each subsequent number is the sum of the previous two. In mathematical terms, the sequence Fn of Fibonacci numbers is defined by the recurrence relation Fn = F(n-1) + F(n-2) with seed values. Source: http://en.wikipedia.org/wiki/Fibonacci_number

DotNetHokage 6 years ago