Find all integers such that the following property holds: if we list the divisors of in increasing order as , then we have
Solution
Consider the property that for integers , the divisors of , listed in increasing order as , satisfy:
To solve this problem, we analyze the differences for the sequence of divisors of .
### Step 1: Analysis for
Calculate . The divisors of are .
- Differences: , , .
Check the condition:
The condition is satisfied for .
### Step 2: Analysis for
Calculate . The divisors of are .
- Differences:
Check the condition:
The condition is satisfied for .
### Step 3: Analysis for
For , consider the additional smaller prime divisors that appear in . These introduce smaller gaps among the divisors of , potentially violating the increasing condition of differences.
For example, for , . The divisors include numbers like 10, 20, 30, etc., introducing nonuniform differences between consecutive divisors. This results in some differences being smaller than preceding differences, violating the original condition.
### Conclusion
The condition is satisfied only for and , as detailed in the stepwise analysis. Therefore, the solution is: