How do I create an arithmetic sequence using the counter function, but only using basic mathematics operations (in this case, addition)

Sq = [2 4 6 8]
N = 3

if (Sq(2) - Sq(1)) == (Sq(end)-Sq(end-1))
    d = Sq(2) - Sq(1)
    disp("The sequence is arithmetic")
    %i would like to use a counter using addition instead of a counter that ranges from values 1 to N. please assist on how to obtain that?
    for i = 1:N
        Sq(end + 1) = Sq(end)+d;
    end
    disp(Sq)
end 

[Fangjun Jiang]

1:10

ans = 1×10

1 2 3 4 5 6 7 8 9 10

1:2:10

ans = 1×5

1 3 5 7 9

1:3:10

ans = 1×4

1 4 7 10

[John D'Errico]

Confusing question. Do you want to create a sequence? Or do you want to determine IF a given sequence is arithmetic? The two are very different problems.

Answer 1

[Walter Roberson]

i = 1;
while i <= N
    sq(end+1) = sq(end) + d;
    i = i + 1;
end

[Fangjun Jiang]

N=10;
d=2;
i = 1;
while i <= N
    sq(end+1) = sq(end) + d;
    i = i + 1;
end

The end operator must be used within an array index expression.

Would mess up the vector length if "sq" was given an initial value

(1:N)*d