I am not sure how to integrate this function by parts.
I would integrate it as follows:
ln(x2-1) = ln(x+1) + ln(x-1)
which integrates to (x+1)ln(x+1)-(x+1) + (x-1)ln(x-1) - (x-1) which you can collect (although it doesn't simplify it much!)
And don't forget the factor of 6.