I was going though this blog and it says
You can represent a list of distinct integers no larger than N using exactly N bits: if the integer i appears in your list, you set the i th bit to true. Bits for which there is no corresponding integers are set to false. For example, the integers 3, 4, 7 can be represented as 00011001. As another example, the integers 1, 2, 7 can be represented as 01100001.
Can someone please explain me how [3, 4, 7] = 00011001 and [1, 2, 7] = 01100001 and also why 8 bits are taken?