there are a few ways to think about passwords
the very short password - easy to remember but easy to guess
the moderately long password - a bit harder to remember but harder to guess.
The very long password - not possible to remember but virtually unbreakable
If we're purely talking about length, repeat characters or patterns should be easy to remember but hard to crack. As far as I'm aware, a brute force password cracker has to hit the password exactly or the result is false, and it goes on to the next iteration. Perhaps I'm way off base, but that's how I understand it.
If your password is 'Ax#135', memorization is easy and a decent cracking algorithm on a fast machine will get it within a few seconds or so. If your password is 'AAAAAxxxxx#####111113333355555' (i.e. 30 characters in length) the cracking algorithm probably won't get around to it for some span of lifetimes, but it will be simple to remember. Not being a cryptographer, I don't know if there are mathematical ways around that dodge. It all comes down to how sensitive is the info you're protecting and how committed are the folks that want it.
You could mix it up the reps:
Axx###111133333555555
or repeat a simple pattern
Ax#135Ax#135Ax#135Ax#135
etc.
I'm a fan of using mnemonic memorizations, for example:
@aPr2m*8d (At a Paris restaurant two movie stars ate dinner)