How can I do this on Calc? (1 | 1’ | 2 | 2’ | 3 | 3’ | …)

I want a row to look the following:

1 | 1’ | 2 | 2’ | 3 | 3’ | … and so on

Is there a way to make it automatically so I don’t have to do it manually? It doesn’t need to be an ’ exactly, could be also * or anything that makes the second “1” e.g. different from the first.

Welcome to the community!
However, something went wrong with the first question. On the one hand, it is simply not clear enough. Whoever wants to help, has to guess what the real intention is.
Secondly: The short version, which is shown as a headline, does not let recognize at all, what the question actually is about.
“How can I make two adjacent columns distinguishable by changing a label (number? color?)” as a headline, and a -depending on the variant- more detailed explanation. That’s it. Well, next time it will work better.
But you can still get better success in the first attempt: Edit (pencil icon!) your question, and add more detailed information. You can also improve the headline.

Welcome!
If you need the real numbers 1, 2, 3, etc. to remain in the cells, but only be displayed with marks, then you can use conditional formatting.
First of all, create some new styles, one for each viewes, and use a custom format code to add the desired annotation to the number.
Now select a row and set one condition and one style for each number of numbers. A formula like COUNTIF($A$1:A$1;A1)=2 will do the job.

Usage example -
DifferentViewForRepeatedValues.ods (9.3 KB)

If you need your row in a cell, you can do that with:

=CONCAT(ROW(1:5) & " | " & ROW(1:5) & "* | ")

In horizontal row in different cells:

=TRANSPOSE(INT(ROW(2:11)/2)&IF(ISEVEN(ROW(2:11)),"","'"))

The second formula must be completed as a matrix formula.

I hope this helps you.

Let me try a third attempt:
Entering in a cell of an odd-numbered column
=INT((COLUMN()-1)/2)+1 + IF(ISODD(COLUMN());0.1;0.2)- 5
where the constant -5 just is an example for a number in this place,
and filling this to the right as far as needed might achive something as was intended.
This way the “as-if-column-title” would be a number without any special formatting.
Throw a glance on
columnNumberingInPairs.ods (10.7 KB)
My most preferred solution is demonstrated there starting at J4 with the directly entered value 1.1 and continues with a formula entered into K4, and then filled to the right by dragging the cell handle.

  • Type 1 and 1’ in the first two cells (first cell must be formatted as Number; the second one could be 1*, 1a, etc.).
  • Select both cells and the following ones that must be modified.
  • Choose menu Sheet - Fill Cells - Fill Series.
  • For Series Type choose AutoFill.
  • OK.