i just read about this... i think.. i can solve this.. but it will be hard.. and doing it using arithmetic and geometric progression should be interesting.. and i know this is late.. so please tell me if any of u guys have already solved it haha. Also here is something interesting i saw when i approached this problem..
look.. i know this is hard to explain but look at how when we take the square root of the numbers we get like... 7, 67, 667, 6667, 66667, 666667..
square numbers 66, 666, 666, 6666, 6666 u will see that 35 is the middle number.. and for 68, 6668, 66668, 666668, u have 62 as the middle number.. its interesting when u do like 61... but there is definately a pattern. I just looked at the problem like 2 mins ago. so I haven't yet thought of a logical explanation. From what i just saw most number in the
