9thheptagonalnumber

<-- Enter heptagonal number statement
  

---

Calculate heptagonal number 9

The formula for heptagonal number n is as follows

Hn  =	n(5n - 3)
	2

Given n = 9, we have:

H9  =	9(5(9) - 3)
	2

H9  =	9(45 - 3)
	2

H9  =	9(42)
	2

H9  =	378
	2

H₉ = 189

---

Run Another Calculation