10 CLS
20 FOR t = 0 TO 9
30 FOR u = 1 TO 10
40   n = 10 * t + u
50   GOSUB 110
60   PRINT USING "##  "; m;
70   NEXT u
80   PRINT
90 NEXT t
100 END
110 IF n = 1 THEN m = 1: RETURN
120 m = 1: f = 2
130 IF n MOD (f * f) = 0 THEN m = 0: RETURN
140 IF n MOD f = 0 THEN GOSUB 180
150 f = f + 1
160 IF f <= n THEN GOTO 130
170 RETURN
180 m = -m
190 n = n / f
200 RETURN
210 END