Macro to autofill a number in empty cells in a column

Hi,
I have two issues:
1. I need a macro to find a unique number, say a 10 digit number starting with 4100.. and move it 1 row down and 3 rows to the left. It needs to look only in one column (E) for this number. This row contains several unique numbers, variable number of blank cells between them, all having 10 digits and starting with 4100.. - So the macro needs to repeat this for every unique number.

2)Once it does this, I need it to autofill the unique number in all the cells in column A until the next unique number is reached.

Can anyone help me with this please?

Thanks.