100 CLS : REM  100 HOME for Applesoft BASIC
110 INPUT "Number of rows: "; ROWS
120 DIM COLSIZE(ROWS)
130 FOR COL = 1 TO ROWS
140   COLSIZE(COL) = LEN(STR$(COL + ROWS * (ROWS - 1) / 2))
150 NEXT
160 THISNUM = 1
170 FOR R = 1 TO ROWS
180   FOR COL = 1 TO R
190     PRINT RIGHT$("  " + STR$(THISNUM), COLSIZE(COL)); " ";
200     THISNUM = THISNUM + 1
210   NEXT
220   PRINT
230 NEXT
240 END