SOLUTION: What is the largest prime factor of 1 + 2 + 3 + 4 + 5 + ... + 60?

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Question 336088: What is the largest prime factor of 1 + 2 + 3 + 4 + 5 + ... + 60?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
What is the largest prime factor of 1 + 2 + 3 + 4 + 5 + ... + 60?
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Use S(n)=(n/2)(1st + last) to get the sum.
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S(60) = (60/2)(1+60) = 30*61 = 1830
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Now find the largest prime factor in 1830
Divide by 2 till you can't.
Then divide by 3 till you can't.
Then by 5
Then by 7
etc.
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I get an answer of 61
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Cheers,
Stan H.