Solving a math problem with planner programming

from blog Computer Things, | ↗ original
The deadline for the logic book is coming up! I'm hoping to have it ready for early access by either the end of this week or early next week. During a break on Monday I saw this interesting problem on Math Stack Exchange: Suppose that at the beginning there is a blank document, and a letter "a" is written in it. In the following steps, only the...