2. Write down the first 15 consecutive odd numbers in a row. Divide the numbers in this row into groups so that the first group contains one number, the second group contains the next two numbers, the third group contains three numbers, and so on. Find the sum of the numbers in each group and indicate the common pattern for all groups.
2. We have

$$
\begin{aligned}
& 1=1^{3} \\
& 3+5=8=2^{3} \\
& 7+9+11=27=3^{3} \\
& 13+15+17+19=64=4^{3} \\
& 21+23+25+27+29=125=5^{3}
\end{aligned}
$$

We can observe the following pattern: if we raise the number of elements in a group to the power of three, we get the sum of the numbers (elements) in that group.