If N is even then let l =n/2, otherwise let l = (n+1)/2. Then,
Note  The xFFT operations are unnormalized, so a call of xFFTF followed by a call of xFFTB will multiply the input sequence by N. The VxFFT operations are normalized, so a call of VxFFTF followed by a call of VxFFTB will return the original sequence.

Original Sequence: 
0.0 + 1.0i 1.0 + 0.0i 0.0 +1.0i 1.0 + 0.0i 
Transformed Sequence: 
0.0 + 0.0i 0.0 + 0.0i 0.0 + 0.0i 0.0 + 4.0i 
Recovered Sequence: 
0.0 + 4.0i 4.0 + 0.0i 0.0 +4.0i 4.0 + 0.0i 