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Turkey number theory
Problem
Find the largest positive integer which is divisible by all positive integers whose cube is not greater than .
Solution
The answer is .
Let us consider the positive integer so that . As satisfies the conditions, we will consider the case when . Note that each of , , and divides and hence divides . Since , divides and divides , we have that
divides . Therefore, and hence .
If or , then , but .
If or , then , but .
If , then , but .
If , then and . Therefore .
Let us consider the positive integer so that . As satisfies the conditions, we will consider the case when . Note that each of , , and divides and hence divides . Since , divides and divides , we have that
divides . Therefore, and hence .
If or , then , but .
If or , then , but .
If , then , but .
If , then and . Therefore .
Final answer
420
Techniques
Greatest common divisors (gcd)Least common multiples (lcm)Floors and ceilings