Answer:
n² + 3
Step-by-step explanation:
The first pattern has 4 squares.
The second pattern has 7 squares.
The third pattern has 12 squares.
The fourth pattern has 19 squares.
When we subtract 3 on each term we get:
1, 4, 9, and 16, which are perfect squares.
So n² is in the formula. Each term is added 3 to the perfect squares.
The nth term becomes n² + 3.