Sum((2*k2-1)/(4k2-1), (k,1,n)) https://www.wolframalpha.com/input?i=Sum%28%282*k2-1%29%2F%284k2-1%29%2C+%28%EF%BD%8B%2C+1%2C+n%29%29&lang=ja
Sum((2*k2-1)/(4k2-1), (k,1,n))
https://www.wolframalpha.com/input?i=Sum%28%282*k2-1%29%2F%284k2-1%29%2C+%28%EF%BD%8B%2C+1%2C+n%29%29&lang=ja