# Euler Problem 64

Euler Problem 64:How many continued fractions for N ≤ 10000 have an odd period?

In Mathematica:

```oddFractionCount = 0;
For[i = 2, i &lt;= 10000, i++,
If[IntegerPart[Sqrt[i]] == Sqrt[i], Continue[]];
If[Mod[Length[ContinuedFraction[Sqrt[i]][[2]]], 2] == 1,
oddFractionCount++]]; oddFractionCount
```

C# Implementacija:

Iskorištena Metoda iz prethodnog problema broj 66, koja izračunava sve kontinualne frakcije:

```using System;
using System.Collections.Generic;
namespace EulerProblem66
{
class Program
{
static void Main(string[] args)
{
int oddPeriod = 0;
for (int d = 2; d <= 10000; d++)
{
if (d % Math.Sqrt(d) == 0)
continue;
List<long> c = ContinedFraction(d);
if (c.Count % 2 == 0)
oddPeriod++;

}
Console.WriteLine(oddPeriod);
///Kraj
Console.WriteLine("Pres any key to continue..");
}

static List<long> ContinedFraction(long d)
{
List<long> e = new List<long>();
long d2 = (long)Math.Sqrt(d);
long a = d2;
long p = 0;
long q = 1;
do
{
p = a * q - p;
q = (d - p * p) / q;
a = (p + d2) / q;
} while (q != 1);

return e;
}

}
}
```