The values in columns A and B are natural numbers, representing the start and end points of the array respectively:

The task is to use the values in columns A and B to generate a string composed of natural number array, and fill in the result in column C, as follows:

Enter in cell C2:

=spl("=to(?1,?2).concat@c()",A2,B2)

Then drag C2 down to every relevant row:

esProc Desktop and Excel Processing
14.1 Generate continuous array
14.3 Expand one row into multiple rows based on value