9thhexagonalnumber

<-- Enter hexagonal number statement
  

Calculate hexagonal number 9

The formula for hexagonal number n is as follows
Hn = n(2n - 1)

Given n = 9, we have:
Hn = 9(2(9) - 1)
Hn = 9(18 - 1)
Hn = 9(17)
H9 = 153