I have a sheet with a column of numbers, some numbers are singular and some appear twice, i would like to add a column after each number or after the second duplicated number.

Ex.
Column A
1
2
2
3
4
5
5
6
7
8
8

I would want a row after 1, the second 2, 3, 4, the second 5, 6 ,7, and the second 8. There will only ever be one or two entries per individual number never more.

Any ideas for a code for this one?

In addition i would also like to automatically highlight that column a certain color up to a certain column.

Thanks.