A question to improve my loop of ODE

I have a question which asks to solve a ODE problem, and I have done the main part codes except one loop. It asks to set dt=2^-2,2^-3,2^-4.....2^-8 for t=[0:dt:5], and finally save the output E for each dt as E_list vector. But I can only do with one dt value, so I want to know how can I improve my codes.(codes are in the figure below)

[Kevin Chng]

change your for

for i=-2:-1:-8