Determine all integers such that every with divides the binomial coefficient .
Solution
We are tasked with determining all integers such that for every integer satisfying , the binomial coefficient is divisible by .
To approach this problem, let's first consider the conditions on . For a given , the range for is . Let , so we need to ensure that the binomial coefficient is divisible by .
### Understanding the Binomial Coefficient
The binomial coefficient can be expressed as:
For this to be divisible by , the numerator must be divisible by , which implies that divides at least one of the terms in the product .
### Analyzing when is Divisible by
For the divisibility condition to be true for every in the specified range, one key requirement is to examine when appears as a factor in . It often occurs that this condition is satisfied when is a prime number because in such cases, the factorial division in the binomial coefficient won't introduce a common factor across the range of .
Therefore, if itself is structured such that every in the range can be non-composite, particularly being a prime, it inherently satisfies the condition that .
### Conclusion
Given this analysis, we can conclude that must be such that every applicable is inherently prime or acts divisibly in the factorial representation—specifically when is a prime number, this condition can be satisfied efficiently.
Thus, the required set of integers that ensures the condition is fulfilled for every in the specified range are all prime numbers. Therefore, the answer is: