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Math Help - For which n does 1+2+...+n divide 1*2+2*3+...(n-1)n

  1. #1
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    For which n does 1+2+...+n divide 1*2+2*3+...(n-1)n

    For which n does \sum_{i=1}^ni divide \sum_{i=1}^n(i-1)i ?
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  2. #2
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    Take note that

    \frac{\sum_{i=1}^{n}i}{\sum_{i=1}^{n}(i-1)i}=\frac{\frac{n(n+1)}{2}}{\frac{n(n-1)(n+1)}{3}}=\frac{3}{2(n-1)}
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