A theater was designed with 15 seats in the first row, 19 in the second row, 23 in the third row, and so on. Write a function that represents this seating pattern to determine how many seats are in any row.
a(n) = 15 + 4(n)
O a(n) = 15 + 4(n-1)
an) = 23 + 4(n)
an) = 23 + 4(n-1)