The formula for the nth term is expressed as
an = (an - 1)^2 - 3
This is a recursive formula
This means that the second term, a2 is
a2 = (a2 - 1)^2 - 3
a2 = (a1)^2 - 3
a2 = 4^2 - 3 = 16 - 3 = 13
a3 = (a3 - 1)^2 - 3
a3 = (a2)^2 - 3
a3 = 13^2 - 3 = 169 - 3 = 166
a4 = (a4 - 1)^2 - 3
a4 = (a3)^2 - 3
a4 = 166^2 - 3 = 27556 - 3 = 27553
Thus,
a4 = 27553
