1, 2, 4, 6 (10% discount), 12 (15% discount), 18 (15% discount), 24 (20% discount), 36 (20% discount), 48 (25% discount), 60 (25% discount), 72 (25% discount), 84 (25% discount), 96 (25% discount), 108 (25% discount), 120 (25% discount), 160 (25% discount), 240 (25% discount), 320 (25% discount), 480 (25% discount)