#triangle number

[collective-evolution]

153 is the 17th triangle number.

[jordandavidhudgens]

Solution to Project Euler Question 12 | Highly divisible triangular number

Sample:

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

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

Problem:

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

Solution:

Johnny Coder had a great solution for this, he opened up Integer class and included the mathn library so we could access the prime_division method and increment the sum value. From there you can iterate until your triangle number hits 500 and then break.

View code and solution

[doculicious]

Beware of plastic water bottles with the #7 in the recycle triangle.