7thnonagonalnumber

<-- Enter nonagonal number statement
  

Calculate nonagonal number 7

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

Given n = 7, we have:
N7  =  7(7(7) - 5)
  2

N7  =  7(49 - 5)
  2

N7  =  7(44)
  2

N7  =  308
  2

N7 = 154