Sub LichThiDauVongTron()
Dim res$(), N&, sR&, i&, j&, k&, d&, t&
Const sDoi& = 32
If sDoi Mod 2 = 1 Then N = sDoi Else N = sDoi - 1
sR = sDoi \ 2
ReDim res(1 To sR, 1 To N)
For j = 1 To N
k = j - 1
d = N
For i = 1 To sR
If k = N Then k = 1 Else k = k + 1
d = d - 2
t = ((k + d - 1) Mod N) + 1
If k < t Then
res(i, j) = k & "_" & t
Else
res(i, j) = t & "_" & k
End If
Next i
If sDoi > N Then res(sR, j) = ((j + N - 2) Mod N) + 1 & "_" & sDoi
Next j
Range("B3").CurrentRegion.Offset(1).ClearContents
Range("B3").Resize(sR, N) = res
End Sub