Find the number of different numbers of the form $\left\lfloor\frac{i^2}{2015} \right\rfloor$, with $i = 1,2, ..., 2015$.
1. We need to find the number of different values of the expression $\left\lfloor \frac{i^2}{2015} \right\rfloor$ for $i = 1, 2, \ldots, 2015$.
2. First, consider the range of $i^2$ for $i$ in the given range. The smallest value of $i^2$ is $1^2 = 1$ and the largest value is $2015^2$.
3. We need to evaluate the floor function $\left\lfloor \frac{i^2}{2015} \right\rfloor$ for these values. 
4. For $i = 1$, we have:
   \[
   \left\lfloor \frac{1^2}{2015} \right\rfloor = \left\lfloor \frac{1}{2015} \right\rfloor = 0
   \]
5. For $i = 2015$, we have:
   \[
   \left\lfloor \frac{2015^2}{2015} \right\rfloor = \left\lfloor 2015 \right\rfloor = 2015
   \]
6. Now, we need to determine if all integers from $0$ to $2015$ can be achieved by $\left\lfloor \frac{i^2}{2015} \right\rfloor$ for some $i$ in the range $1$ to $2015$.
7. Consider the expression $\left\lfloor \frac{i^2}{2015} \right\rfloor = k$ for some integer $k$. This implies:
   \[
   k \leq \frac{i^2}{2015} < k+1
   \]
   Multiplying through by $2015$, we get:
   \[
   k \cdot 2015 \leq i^2 < (k+1) \cdot 2015
   \]
8. For each integer $k$ from $0$ to $2015$, we need to check if there exists an integer $i$ such that:
   \[
   k \cdot 2015 \leq i^2 < (k+1) \cdot 2015
   \]
9. Since $i$ ranges from $1$ to $2015$, $i^2$ ranges from $1$ to $2015^2$. The intervals $[k \cdot 2015, (k+1) \cdot 2015)$ for $k = 0, 1, \ldots, 2015$ cover the entire range from $0$ to $2015^2$.
10. Therefore, for each $k$ from $0$ to $2015$, there exists at least one $i$ such that $k \cdot 2015 \leq i^2 < (k+1) \cdot 2015$.
11. Hence, all integers from $0$ to $2015$ are achievable by $\left\lfloor \frac{i^2}{2015} \right\rfloor$ for some $i$ in the range $1$ to $2015$.

The final answer is $\boxed{2016}$.