Return consecutive duplicates and non-duplicates from a column.

[excelhelpfred]

I have the following data set in Column A of sheet 1.
CASE
1-123
1-123
1-123
5-001
1-111
1-123
1-001

I would like to return all consecutive duplicates & non-duplicates onto Column A of sheet 2. DESIRED OUTPUT:
CASE
1-123
5-001
1-111
1-123
1-001

This is what I've got so far.
I made a helper column. Next to the first CASE I put a 1. Below I put the formula =if(A3=A2,2,1).
CASE
1-123 1
1-123 2
1-123 2
5-001 1
1-111 1
1-123 1
1-001 1

I then entered the formula =INDEX(A2:B8,MATCH(1,B2:B8,0),1) which returned
1-123
5-001
5-001
5-001
1-111
1-123
1-001

Any help would be much appreciated!
Sorry for the ugly formatting, I'm using free Excel off OneDrive so I'm having issues downloading my spreadsheets.

[bebo021999]

You have two options, with or without helper.
With helpers:
B2:
=IF(A1=A2,"",MAX($B$1:$B1)+1)
C2:
=IFERROR(INDEX($A$2:$A$8,MATCH(ROW(1:1),$B$2:$B$8,0)),"")
Without helper:
B2:

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[excelhelpfred]

Solved!
Thanks!
($A$1:$A$7<>$A$2:$A$8),ROW(1:1)
So if A1 to A7 does not equal A2 to A8, go down a row?

[excelhelpfred]

Also, is there a way to make the formula dynamic because Column A will continue to have new entries?

[bebo021999]

Also, is there a way to make the formula dynamic because Column A will continue to have new entries?

Expand the range to, i.e, 100:

=IFERROR(INDEX(A:A,AGGREGATE(15,6,ROW($A$2:$A$101)/($A$1:$A$100<>$A$2:$A$101),ROW(1:1))),"")