\sum_{k=1}^n \prod_{l=1}^m (k+l-1)=\frac{1}{m+1}\prod_{l=1}^{m+1}(n+l-1)
Embed the image to your blog in HTML, Markdown, Textile, BBCode.
Recent Referers:
  1. http://formula.s21g.com/?%5Csum_%7Bk=1%7D%5En%5Cprod_%7Bl...
  2. http://blog.s21g.com/lvs/
  3. http://blog.s21g.com/?page=7