hacker.org

According to wolframalpha the sum of the first billion ends with 90.6, so the phyton code should actually print out a number ending with 90 because it does not round properly.

http://www.wolframalpha.com/input/?i=10 ... 81%2B7*Sum[1%2F%28%284k%2B1%29^2%2B2%284k%2B1%29%29,{k,0,1000000000000}]%29

5el wrote:According to wolframalpha the sum of the first billion ends with 90.6, so the phyton code should actually print out a number ending with 90 because it does not round properly.

So finally it seems the information that the result and it's neighbours shoult be tested is correct hint .