It looks like you've provided a single row or a sequence of numbers: $2, 1, 3, 5$. Could you please clarify how you'd like to proceed with these numbers? Here are a few possibilities:

1. Matrix Formation: Would you like to use these numbers to form a matrix? If yes, specify the size (e.g., 2x2 matrix, 1x4 row vector, etc.).

2. Matrix Operation: If you're continuing from the previous problem, would you like to add this row to the previous matrix or perform some operation with it?

3. Linear Equations: Are these coefficients of a linear equation or system of equations that you'd like to solve?

4. Sequence Analysis: Would you like to analyze the sequence, like finding the mean, variance, or some other statistical property?

5. Vector Operation: Do you want to treat this as a vector and perform operations like dot product, cross product, etc.?

Let me know how you'd like to proceed, and I'll help you with the next steps!