How do you choose an ideal hash function for GetHashCode - gethashcode

Question

What hash function would work for a set of ints that range from say 0-10000? The built-in stuff is a collide-a-thon in this scenario.
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using Xunit;
using Xunit.Abstractions;
namespace Solution.Tests
{
public class HashCodeCollisions
{
public HashCodeCollisions (int field1, int field2, int field3, int field4)
{
Field1 = field1;
Field2 = field2;
Field3 = field3;
Field4 = field4;
}
public int Field1 { get; set; }
public int Field2 { get; set; }
public int Field3 { get; set; }
public int Field4 { get; set; }
public override int GetHashCode () => HashCode.Combine (Field1, Field2, Field3, Field4);
}
public class CreateHashCodeCollisions
{
public CreateHashCodeCollisions (ITestOutputHelper output)
{
Console.SetOut (new Converter (output));
}
[Fact]
public void Find_HashCode_Collisions ()
{
HashSet<int> crashTestDummy = new HashSet<int> ();
int n = 100; // needs to work for 0-10000
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
for (int k = 0; k < n; k++)
{
for (int l = 0; l < n; l++)
{
int hashCode = new HashCodeCollisions (i, j, k, l).GetHashCode ();
bool added = crashTestDummy.Add (hashCode);
if (!added)
{
Console.WriteLine (string.Format ("{0} {1} {2} {3} => {4}", i, j, k, l, hashCode));
}
}
}
}
}
}
}
public class Converter : TextWriter
{
ITestOutputHelper _output;
public Converter (ITestOutputHelper output)
{
_output = output;
}
public override Encoding Encoding
{
get { return Encoding.UTF8; }
}
public override void WriteLine (string message)
{
_output.WriteLine (message);
}
public override void WriteLine (string format, params object[] args)
{
_output.WriteLine (format, args);
}
public override void Write (char value)
{
}
}
}