Welcome to the forum - glad to have you here!
Give this a go:
- created a one column physical table, with the following calculated column:
Sequence = GENERATESERIES( 1, 100, 1)
This will provide the first column of your desired table
created a measure to count the number of rows in the data table where the quantity equals the value of our GENERATESERIES column from above:
Count Quantity =
COUNTROWS( Data ),
Data[Quantity] = SELECTEDVALUE( 'Sequence'[Quantity] )
Full solution file posted below. Hope this is helpful.