Common C# test type thangs

grain.cs

using System;

/// <summary>
/// Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
/// </summary>
public static class Grains
{
    public static ulong Square(int n)
    {
        if (n <= 0 || n > 64)
            throw new ArgumentOutOfRangeException();

        return (ulong)Math.Pow(2, n - 1);
    }

    public static ulong Total()
    {
        ulong total = 0;
        for (var i = 1; i < 65; i++)
            total += Square(i);

        return total;
    }
}