Question 22
As shown in the diagrams below, the first four 7-gonal numbers are 1, 7, 18 and 34, which correspond to the number of black dots in each diagram from left to right, respectively.
If 616 is the $m$th 7-gonal number, then what is the value of $m$?
If 616 is the $m$th 7-gonal number, then what is the value of $m$?