Simple c code need explanation

I’ve recently started studying c programming and I have a piece of code but cannot figure out how it gives me the result.

int i, j, v, a(6) = {1, 3, 1, 3, 1, 3};
for (i=0; i<5; i++) 
{
    v = 0;
    for (j=0; j<2; j++) 
    {
     v += a(i+j);
    }
    
    printf("%d,", v/2);
}

It prints out 2,2,2,2,2, but I don’t know why. Can someone explain? I know it’s an easy task but I’m a rookie in coding.