# What Pascal Identity Should I use?

**Number Theory**Level 3

Let \(b_{k,n}\) be the \(k^\text{th}\) element of the \(n^\text{th}\) row of Pascal's triangle, with row \(1\) being \(\{1\}\), row \(2\) being \(\{1,1\}\), etc. Also the \(1^\text{st}\) element of each row is \(1.\) Find the value of
\[(b_{3,2015})^2 - \sum_{i=1}^{2013} i^3.\]

**Details and Assumptions**:

For example, \(b_{1,1} = 1, b_{2,3} = 2\) and \(b_{5,6} = 5.\)