2
votes
0answers
160 views

Project Euler (memory and speed issues)

Let n be a positive integer. An integer triple (a, b, c) is called a factorisation triple of n if: 1 ≤ a ≤ b ≤ c a·b·c = n. Define f(n) to be a + b + c for the factorisation triple (a, b, c) of n ...
23
votes
4answers
1k views

What is the fastest way to count square-free words?

Background A word is a string of letters in an alphabet. A square-free word has no adjacent repeating substring. For example, (in the ternary alphabet of {0,1,2}) the words 00, 012121, and 0212012021 ...