I am not sure that I understand the question.
Do you mean
a 1=1
a n+1 = 4 + 2(a n) 1/3
so the sequence is 1, 6, 4+2*(6 1/3), 4 + 2[4+2*6 1/3] 1/3, .....
Also, what is nEZ+ I am not familiar with this notation.
It does look hard. If you tell me that my interpretaion is correct then I will give it a go.