3rdhexagonalnumber

<-- Enter hexagonal number statement
  

Calculate hexagonal number 3

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

Given n = 3, we have:
Hn = 3(2(3) - 1)
Hn = 3(6 - 1)
Hn = 3(5)
H3 = 15