Question:
What are the uses of Pascal's Triangle? What are some interesting properties of Pascal's Triangle?
I know that Pascal's Triangle has many uses, but I only know a few of them. I know that the binomial theorem is based on Pascal's Triangle, and I know that the $r$'th element of the $n$'th row is determined by: $$_{n}C_{r}=\binom{n}{r}=\frac{n!}{r!(n-r)!}$$ I also know some interesting properties of Pascal's Triangle. I know that the sum of the elements in the $n$'th row is determined by $2^n$, and I know that if there is a prime number in any row, all the other numbers (except $1$) will be divisible by that prime number.
What other uses / properties of Pascal's Triangle are there?
