# rgb_at_sum.py

# rgb_at_sum.py

combos = []
def rgb_at_sum(target_sum):
    min_g = target_sum - 256
    for r in range(256):
        for g in range(min_g, target_sum - r + 1):
            b = target_sum - r - g
            rgb = r, g, b
            print(rgb, sum(rgb), [target_sum])
            combos.append(rgb)

target_sum = 128 * 3 # or any other desired target sum
rgb_at_sum(target_sum)
print(len(combos))