10 FOR Y = 1750 TO 2021
20 GOSUB 1000
30 IF L = 1 THEN PRINT Y;" ";
40 NEXT Y
50 END
1000 L = 0
1010 IF Y MOD 4 <> 0 THEN RETURN
1020 IF Y MOD 100 = 0 AND Y MOD 400 <> 0 THEN RETURN
1030 L = 1
1040 RETURN