The series you provided is:

$8 + 12 + 16 + 20 + 24 + 28$

This is an arithmetic series where the first term $a_1 = 8$, and the common difference $d = 4$.

To express this in sigma notation:

$\sum_{n=1}^{6} (4n + 4)$

This represents the sum of the first 6 terms, where the general term $4n + 4$ gives each term in the series.

Would you like further details on how to construct sigma notation for arithmetic series or have any other questions?

---

Here are five questions related to this concept:

1. How do you find the sum of an arithmetic series?
2. What is the general form of an arithmetic sequence?
3. How do you determine the number of terms in a series?
4. Can you convert any sequence into sigma notation?
5. What are the differences between arithmetic and geometric series?

Tip: Sigma notation is useful for representing long sums in a concise way, especially when dealing with arithmetic or geometric progressions.