The core of this formula is the ROUNDUP function. The ROUNDUP function works like the ROUND function except that when rounding, the ROUNDUP function will always round the numbers 1-9 up. In this formula, we use that fact to repeat values.
To supply a number to ROUNDUP, we are using this expression:
Without a reference, COLUMN generates the column number of the cell it appears in, in this case 3 for cell C4.
The number 2 is simply an offset value, to account for the fact column C is column 3. We subtract 2 to normalize back to 1.
Cell B4 holds the value that represents the number of times to "repeat" a count. We've locked the column reference so that the repeat value remains fixed as the formula is copied across the table.
The normalized column number is divided by the repeat value and the result is fed into ROUNDUP as the number to round. For number of places, we use zero, so that rounding goes to the next integer.
Once the column count is evenly divisible by the repeat value, the count advances.
Rows instead of columns
If you need to count in rows, instead of columns, just adjust the formula like so: