The Minimal Algebraic Equation Satisfied by the Generating Function Enumerat\ ing 123-Avoiding Words of length, n in the alphabet {1, ...,n}, where Each Letter Appears Exactly, 1, Times . By Shalosh B. Ekhad Theorem: Let a(n) be the number of words in the alphabet {1, ...,n} where ea\ ch letter occurs exactly, 1, times and that avoid the pattern 123, in other words, there do not exist i1