Count Position of Filtered TEXT cells in a column

[Sam via OfficeKB.com]

Hi All,

I have a column of Firstnames and would like to count their positon in the
column. If a name matches the name directly beneath it, a count of zero
should be returned. If not, a sequential count of the number of Rows away
from the last time it appeared in the list is needed.
First Row of data starts in Row 11 Column "C". Results for the returned
Count use the same Row, Column "D". The expected "filtered" Results should
count only the visible cells. The first returned count in Column "D" -
filtered or unfiltered must be zero.

Example of Unfiltered Columns:

RowNo. Sequential Count Column "C" Column "D"
11 1 Sharon 0
12 2 Terry 1
13 3 Robert 2
14 4 Sam 3
15 5 Dave 4
16 6 Sam 1 17
7 Jan 6
18 8 Sam 1
19 9 Jay 8
20 10 Robert 6
21 11 Deborah 10
22 12 Deborah 0
23 13 Sharon 11
24 14 Rita 13
25 15 Jay 5



Expected Filtered Results:

RowNo. Sequential Count Column "C" Column "D"


13 3 Robert 0
14 4 Sam 1
16
6 Sam 0
17 7 Jan 3
18 8 Sam 1
19 9 Jay 5
20 10 Robert 5
21 11 Deborah 7
22 12 Deborah 0

24 14 Rita 9


Kind regards,
Sam