Solving equation with increasing value by multiplication

Hello, I am trying to create a code to calculate the area of a triangle with a range of length. And these length number are twice the previous number. Basically, first is 2, then 4, 8, 16, 32, 64, 128. Its breadth stays the same.

Code.

a =[1:???:128]
for i=1:length(a)
    y=a(i)*100/2
end

I appreciate all your help in advance.

Answer 1

[James Tursa]

a = 2.^(1:7);

Answer 2

[Faith Bagire]

The best way that worked for me is using a while loop!

a=1;
while a < 128
     y=a*100/2
     a=a*2;
end