What about

j
D
A D

???


For your example:

A2: =A1
A3: =A1 & " " & B1
A4: =A1 & " " & B1 & " " & C1
A5: =B1 & " " & C1

Not sure what you mean by "the total of numbers that are entered in row
1 can differ" - aren't you entering letters?


In article ,
Mally wrote:

How do I display all combinations of a set of letters in row 1? The total of
numbers that are entered in row 1 can differ.

Example
Cell A1 = H Cell B1 = j Cell C1 =D

The following will be displayed in individual cells starting in Cell A2
A
A j
A j D
j D