Can you use Index() for this?
Yes, it is giving only '1', not the sequence start from 1 to 15. or am I missing something here?
You could just create 15 calculated fields and line them up. Later you can filter things based on which one is clicked. If they were each their own sheet, you could use filter actions on a dashboard to bring up other sheets or launch URL's. Any number of things can be done that don't have to be complicated.
No, I have only one sheet with project name & project count. So If I select 10 then only those records needs to be filtered.
I think Tableau doesn't support LOOP. Correct?
I tried one more option...
select 1 as N from dual
select 15 dual
I used BIN to generate the numbers, but how to reduce the space between the shapes?
You should be able to slowly move your mouse along the space between two shapes and find the line for the grid they are actually sitting in. Once you find the line, you can move it to the left to compress the space.