Question 23
Bob is writing down positive integers, from left to right, starting from 1. After every 7 digits, he inserts an “@” sign. For example: 1 2 3 4 5 6 7 @ 8 9 1 0 1 1 1 @ 2 1 3 1 4 1 5 @ … and so on. What are the three digits, in exact order, immediately after the 100th “@”?