8thnonagonalnumber

<-- Enter nonagonal number statement
  

Calculate nonagonal number 8

The formula for nonagonal number n is as follows
Nn  =  n(7n - 5)
  2

Given n = 8, we have:
N8  =  8(7(8) - 5)
  2

N8  =  8(56 - 5)
  2

N8  =  8(51)
  2

N8  =  408
  2

N8 = 204