Since we have the recursive formula, we can find the value of a₂, a₃, and a₄.

To find the value of a₂, we replace the value of a₁ in the above equation, and we operate:

Now, to find the value of a₃, we replace the value of a₂ in the recursive formula, and we operate:

Finally, to find the value of a₄, we replace the value of a₃ in the recursive formula, and we operate:

Therefore, the value a₄ is the 12.