private static void Main(string[] args)
{
var validCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ9".ToList();
const int len = 81;
var cnt = 10;
using (var rng = new RNGCryptoServiceProvider())
{
while (cnt > 0)
{
var sb = new StringBuilder(len);
while (sb.Length < len)
{
var nextUint = rng.GetNextUint();
var nextIndex = (int)(nextUint % validCharacters.Count);
var nextCharacter = validCharacters[nextIndex];
if (validCharacters.Contains(nextCharacter))
{
sb.Append(nextCharacter);
}
}
var seed = sb.ToString();
var diversity = validCharacters.Count(character => seed.Contains(character));
if (diversity < validCharacters.Count || seed.Length != len)
{
continue;
}
Console.WriteLine(seed);
cnt--;
}
}
}