The first few heptagonal numbers are 1, 7, 18, 34, etc.

The nth heptagonal number can be found using the following formula:

n(5n - 3)

So if you wanted to find the 1,138th heptagonal number you plug it in as:

1,138(5*1,138-3)

1,138*5,687

6,471,806

So as you can see by using the formula shown above the 1,138th heptagonal number is 6,471,806

The first few hexagonal numbers are 1, 6, 15, 28, 45, etc.

The nth hexagonal number can be found using the following formula:

n(2n-1)

So if you wanted to find the 651st hexagonal number you would plug it in as:

651(2*651-1)

651*1,301

846,951

So as you can see by using the formula shown above the 651th hexagonal number is 846,951

The first few pentagonal numbers are 1, 5, 12, 22, 35, 51, 70, etc.

The nth pentagonal number can be found using the following formula:

n(3n-1)/2

So if you wanted to find the 272nd pentagonal number you would plug it in as:

272(3*272-1)/2

272*815/2

110,840

So as you can see by using the above formula the 272nd pentagonal number is 110,840

The first few square numbers are 1, 4, 9, 16, 25, 36, 49, etc.

The nth square number can be found using the formula n² where n is an interger. A square number is also called a perfect square.

So if you wanted to find the 348th square number you would plug it in as:

348²

121,104

So as you can see the 348th square number is 121,104

So if you wanted to find the 400th square number you would plug it in as:

400(400+1)/2

400*401/2

80,200

So as you can see by using the formula the 400th square number is 80,200