The sequence of triangle numbers is generated by adding the natural numbers. So the 7th 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 and 28: 1,2,4,7,14,28
We can see 28 is the first triangle number to have over 5 divisors.
What is the value of the first triangle number to have over n (e.g. 500) divisors?