Are these correct?

Question

a1=(-3x1)2 +4=13
a2=(-3x2)2+4-40
a3=(-3x3)2+4=85
a4=(-3x4)2+4=148
a5=(-3x4)2+4=229
a6=(-3x4)2+4=328

The first six terms of the sequence are 13, 40, 85, 148, 229, 328

I keep coming up with these answers but there is suppose to be an error somewhere.

Answer 1

As you wrote it before,

-3x^2+4 = -3(x^2) + 4

You have tabulated (-3x)^2 + 4, which is very different