Pascal Triangle is very famous in number theory. Interested persons can read about Pascal's triangle at following Wikipedia article – https://en.wikipedia.org/wiki/Pascal%27s_triangle
Anyway, whether read it at Wikipedia or not, below is Pascal's triangle. One look at it and you will understand the pattern.
Now, the challenge before you is following –
1. Put 1 in L2.
2. You need to write a formula which can be put in the row below and dragged left/right and down to create Pascal's Triangle.
You may post your answer in comments section.
Note – Solution to this challenge will be published after 1 month i.e. on 23-Nov-15.