Logica pra gerar nomes sequencial igual as colunas do excel.

Logica.cs

using System;

namespace LogicaSequencial
{
    class Program
    {
        static void Main(string[] args)
        {
            for (int i = 0; i < 100; i++)
            {
                string code = ExcelColumnFromNumber(i);
                Console.WriteLine(i + ": " + code + "->" + NumberFromExcelColumn(code).ToString());
            }
        }

        
        public static string ExcelColumnFromNumber(int column)
        {
            string columnString = "";
            decimal columnNumber = column;
            while (columnNumber > 0)
            {
                decimal currentLetterNumber = (columnNumber - 1) % 26;
                char currentLetter = (char)(currentLetterNumber + 65);
                columnString = currentLetter + columnString;
                columnNumber = (columnNumber - (currentLetterNumber + 1)) / 26;
            }
            return columnString;
        }

        public static int NumberFromExcelColumn(string column)
        {
            int retVal = 0;
            string col = column.ToUpper();
            for (int iChar = col.Length - 1; iChar >= 0; iChar--)
            {
                char colPiece = col[iChar];
                int colNum = colPiece - 64;
                retVal = retVal + colNum * (int)Math.Pow(26, col.Length - (iChar + 1));
            }
            return retVal;
        }
    }
}