For how many positive integers $n$ does $1+2+\cdots+n$ evenly divide $6n$?
Question:
For how many positive integers $n$ does $1+2+\cdots+n$ evenly divide $6n$?
Answer:
Let's think step by step.

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For how many positive integers $n$ does $1+2+\cdots+n$ evenly divide $6n$?
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