So far, so good.
Take your current result, and:
Add the digits until you get only one digit.
(i.e.: 64 = 6 + 4 = 10 = 1 + 0 = 1)
If the number is less than 5, add five.
Otherwise, subtract 4.
Multiply that result by 2.
Subtract 6 from the latest result.
Continue Experiment