N = 5
o = rand(1, N)
n = zeros(1, N)
Lap = [
  -1   1   0   0   0;
   1  -2   1   0   0;
   0   1  -2   1   0;
   0   0   1  -2   1;
   0   0   0   1  -1
]
for i = 1:N
    if i == 1
        i_links = i;
    else
        i_links = i-1;
    end
    if i == N
        i_rechts = i;
    else
        i_rechts = i+1;
    end
    n(i) = o(i_links) + o(i_rechts) - 2 * o(i);
end
n