>//upd:
>if this an attempt to recreate Als letter shuffling from chatter, you are probay correct to go for recursive and have a strikeout list as parameter to signify already used letters. But this will only get you 7!+6!+5! words, so slightly less than 6000.

I think it is

(7 * 6 * 5 * 4 * 3 * 2 * 1) + (7 * 6 * 5 * 4 * 3 * 2) + (7 * 6 * 5 * 4 * 3)
or 
 7! + 7! / 1! + 7! / 2!

>
>>>>I'm trying to write code that will generate valid English words from an array of seven letters.
>>>>string[] letters = new string[] { "g", "a", "u", "n", "t", "l", "e", "t' };
>>>>
>>>>I don't want words with fewer than 5 characters.
>>>>The word must contain (anywhere) the first letter in the array
>>>>I want to write the valid words to a text file.
>>>>
>>>>I think that the word generation can be done recursively but I've been getting nowhere.
>>>>
>>>>Any ideas?
>
>>>http://csharphelper.com/blog/2014/09/generate-random-strings-in-c/
>>Thank you, Borislav but I don't think that will do it.
>>I want to generate the 800K+ possible words (7^7) and test them.