How to populate blank cells with sequence until nonblank cell is encountered?

Try this code in a general module:

Sub BuildSeq()
Dim rng As Range

Set rng = [G1]
rng.Value = 0.01
Set rng = Range(rng, rng.End(xlDown).Offset(rowOffset:=-1))
rng.DataSeries Type:=xlLinear, Step:=0.01
End Sub

Is that something you can work with?