Code to Extract and Concatenate D/M/Y from Column of Julian Dates

Hello.

Working on a simple part of code but having trouble.

Have a list of Julian dates in a column and would like to write a loop to go through each, identify the year, month and day with the respective functions, and then concatenate the results into a certain form.

Having a bunch of problems and would appreciate help with any.

1. Currently using this line
Do Until IsEmpty(Range("A3:A").Offset(i.0))
to move down the column - is there any need for .End(xlDown) somewhere here?

2. Am not sure how to initiate a counter to go down through - have something like this for now:
For i=0 to 9
ActiveCell.Offset(i,1)=Y
ActiveCell.Offset(i,2)=M
Next i

3. Finally after I eventually clear those hurdles, do not know how to concatenate the variables properly: Y&M&D do not seem to work.

Thanks!

Yes I saw such formulas when searching earlier but this is an intermediary step before concatenating the Y, M, D into a specific format (namely, YYYYMMDD).

Here is the disastrous bits of code I have so far!

Sub DateExtract()

Dim Y As Long
Dim M As Long
Dim D As Long
Dim TestDate As String
Dim i As Integer
'Dim counter As Integer

'Sheets("Series").Range ("A3:A200")
'Do While Not IsEmpty(ActiveCell.Offset(1, 0))

Do Until IsEmpty(Range("A3:A").Offset(i, 0))
'Range(ActiveCell, ActiveCell.End(xlDown))

Y = year(ActiveCell)
M = Month(ActiveCell)
D = Day(ActiveCell)

For i = 0 To 9
ActiveCell.Offset(i, 1) = Y
ActiveCell.Offset(i, 2) = M
ActiveCell.Offset(i, 3) = D
Next i
Loop

'TestDate = "Y&M&D"

End Sub

'Exit Do
'Loop Until IsEmpty(ActiveCell)
'Cells.Range(A3,A50)IsEmpty=False
'IsEmpty(ActiveCell) = False
'ActiveCell.Offset(0,1,)=year(ActiveCell)