The problem is that my answer is different from answer i get in MATLAB.
My answer is $(6, -2-2i, -2, -2+2i)$ while MATLAB answer is $(6, -2+2i, -2, -2-2i).$ In MATLAB i use command fft([0 1 2 3]).
How do i compute: $y_1 = 1w_4^1 + 2w_4^2 + 3w_4^3 = i - 2 - 3i = -2-2i$
EDIT: Thanks to par i found out that in MATLAB $ω_n=e^{(−2πi)/n}$ while i use $ω_n=e^{(2πi)/n}.$ So, solved.