What is the greatest prime factor of 1+2+3+。。。+52?	Pick.
A) 53  B) 29  C) 31  D) 37  E) 41
find the sum from direct formula = n(n+1)/2 = 52(52+1)/2 = 26*53...   53 is a PRIME number, so ans is 53..   53 is the answer
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What is the greatest prime factor of 1+2+3+。。。+52?