For the 20th term, $a_20 = 3(20) - 1 = 59$. However, the question asks for the count of terms, not the value. Since the sequence starts at $n = 1$ and ends at $n = 20$, there are $\boxed20$ numbers.Question: A square has a perimeter of $ 40 \, \textcm $. If each side is increased by $ 2 \, \textcm $, by how many square centimeters does the area increase? - Nelissen Grade advocaten