User blog comment:Milesman34/Self Factorial Function/@comment-30754445-20170625054947

Nice function.

Your notation for f(6) to f(10) is wrong though. 10↑↑616478 is a power tower of 616478 10's, which is much larger than the number you meant to write there (1010 10 10 10 10 16478    )

If you want to write "a power tower of 6 tens with 16478 on top" you can use Saibian's Hyper-E notation:

E16478#6

or in my binary letter notation:

16478F6