訂正:
Dim a As Long, b As Long, x As Long, y As Long
a = Range("A1").Value
x = InputBox("回数を入力")
y = InputBox("停止位置を入力")
For i = 1 To y
b = Int((i - 1) Mod x)
Cells(i, 1).Value = b * 100 + a
Next i