Question

Let H(n) be the number of circles you need to form a hexagon with n circles on each edge. It is clear that
H(2) = 7
and
H(3) = 19.


It can be shown that increasing the number of circles on each edge gives the following recurrence relation:
H(n) = {1 if n = 1
H(n) = {H(n − 1) + 6n − 6 if n > 1.
Calculate H(9)

Answer 1

had to calculate H(4-8) to get the answer wand H(8)=169
H(8)+6*9-6=217

Answer 2

correct. :)