Need a function to generate short names, how best to compose an algorithm?

Question

PHP

There is an array with ordinary words, the word is the key of the array.
And in the value for each element you need to write the following:
a, b, c ... z,
ab, ac, ad ... za, zb, zc,
a1, a2, a3.. z7, z8, z9,
Whatever in as a result, get about 1k non-repeating, as short as possible letter combinations (+ then numbers when the letter combinations run out)

Answer 1

UPD. Didn't notice PHP in the tags.
Google permutations. First link:
https://stackoverflow.com/questions/5506888/permut...