Thử code
Sub XYZ()
Dim res(), a&(1 To 7), fYear&, lYear&, i&, j&, t
fYear = Range("C1").Value 'Nam dau
lYear = Range("F1").Value 'Nam cuoi
ReDim res(1 To (lYear - fYear + 1) \ 7 + 5, 1 To 7)
For i = fYear To lYear Step 4
t = i & "/2/29"
If IsDate(t) Then
j =...