User blog comment:Ikosarakt1/Coding strings as ordinals (for Friedman's n(k))/@comment-5029411-20130729191800

Here is my order type using n letters.

The starting number is zero

The first letter is A, A@ = w^@, second letter is B = epsilon_@, C = zeta_@, D = eta_@, etc.

Numbers can be right order, ...DD...DDCC...CCBB...BBAA...AA

The result order type is phi(w,0).