For loop nested in while loop problem

I have written a while loop that is supposed to determine the value of the parameter "n" for "a" to exceed the value 300. I know "n" should be 17, but I'm getting a value of 4 instead. Does anyone see the problem?

The code is as follows:

a = 10;
k = 0.5;
n = 2;
while a < 300
    for m = 1:5
        a = a + (a*k) + n;
    end
    n = n + 1;
end

Answer 1

[Terry]

I realized that I didn't reinitialize my "a" variable, thanks to Barmar's comment. Although the code might not look very efficient, this is what works for me:

    a = 10;
    k = 0.5;
    n = 2;
    while a < 300
        a = 10;
        for m = 1:5
            a = a + (a*k) + n;
        end
        if a >= 300
            break
        end
        n = n + 1;
    end

Answer 2

[Azzi Abdelmalek]

Why are you using a for loop from 1 to 5? You are not supposed to increment n instead of m?

[Terry]

I want to increment both "n" and "m." The "m" is supposed to iterate "a" 5 times for every new "n" value until "a" exceeds 300.

[Anthony]

matlab is telling you the correct answer. iterating the following for 5 times will give a pretty large number.

a = a + (a*k) + n;