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012 - Highly Divisible Triangular Number

Problem 12 / Challenge #12: Highly Divisible Triangular Number

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:

$$1, 3, 6, 10, 15, 21, 28, 36, 45, 55, \dots$$

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

$$\begin{align} \mathbf 1 &\colon 1\\\ \mathbf 3 &\colon 1,3\\\ \mathbf 6 &\colon 1,2,3,6\\\ \mathbf{10} &\colon 1,2,5,10\\\ \mathbf{15} &\colon 1,3,5,15\\\ \mathbf{21} &\colon 1,3,7,21\\\ \mathbf{28} &\colon 1,2,4,7,14,28 \end{align}$$

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

What is the value of the first triangle number to have over five hundred divisors?

ProjectEuler+ Problem Statement

The Project Euler problem is equivalent to the ProjectEuler+ challenge with $T = 1$ and $N = 500$.