class: list # welcome to discussion 3! Schedule: - Post-MT1 - Recursion - More Recursion - Sign in: **links.cs61a.org/addison-attendance** - Feedback: **links.cs61a.org/addison-feedback** --- class: title # recursion --- class: title # recursion a look at factorial: $$n! = n * (n-1)!$$ --- class: title # recursion a look at factorial: $$n! = n * (n-1)!$$ $$0! = 1$$ --- class: title # recursion a look at factorial: ```python def factorial(n): if n == 0: return 1 else: return n * factorial(n-1) ``` --- class: title # hailstone --- class: title # is_prime