Arrays/ Task - 5 Maximal Increas

using System;
class MaximalIncreas
{
    static void Main()
    {
        int[] mainArray = new int[] { 1, 2, 5, 5, 3, 1, 2, 3, 4, 6, 2 };
        int length = 1;
        int count = 1;
        string arrayNums = mainArray[0].ToString() + " ";
        string longestSequence = "";

        for (int start = 0; start < mainArray.Length-1; start++)
        {
            if (mainArray[start] == mainArray[start+1]-1)
            {
                count += 1;
                arrayNums += mainArray[start + 1] + " ";
            }
            if (count > length)
            {
                length = count;
                longestSequence = arrayNums;
            }
            else if (mainArray[start] != mainArray[start + 1]-1)
            {
                count = 1;
                arrayNums = mainArray[start + 1] + " ";
            }
        }
        Console.WriteLine(length);
        Console.WriteLine(longestSequence);
    }
}