Ok, I'm confused, what exactly is the point here? If you don't care, 3.14 is sufficient, if you do care then you use π, and if you really care you use τ[1].
Did you read the article? He explains very precisely what he means and what his conclusion is. "Rational" in the context of the title means "one integer divided by another to which the first is relatively prime", and the word "useless" indicates that there is no gain in accuracy/complexity in comparison to the decimal notation for a rational number (where you express a rational number as an integer divided by an implicit power of ten).
The point is that you should just memorize whatever precision decimal you need. There's no shortcut like 22/7 that will magically give you more accuracy and be easy to memorize.
It would have been better if I had specified absolute values in the formula. I hope the point came through. (It appears I'm unable to edit this particular comment.)
[1](http://tauday.com/tau-manifesto)
(And if you really really really care, you use a different font then the one HN defaults too.)