You are multiple of 8 such as the numbers you have listed. 104, 112, 120, 128, 136, 144. They form an arithmetic series whose first term is 104, and the common difference is 8. In other words: 104+8=112. 112 + 8=120. 120 + 8=128. 128 + 8 =136. 136 + 8 =144. And that is it.