The sequence of triangle numbers is generated by adding the natural numbers. So the 7^{th} triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:

1, 3, 6, 10, 15, 21, 28, 36, 45, 55, …

Let us list the factors of the first seven triangle numbers:

** 1**: 1

** 3**: 1,3

** 6**: 1,2,3,6

**10**: 1,2,5,10

**15**: 1,3,5,15

**21**: 1,3,7,21

**28**: 1,2,4,7,14,28

We can see that 28 is the first triangle number to have over five divisors.