All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars
 perplexus dot info

 A peculiar triangular number (Posted on 2015-12-10)
28 is the smallest triangular number to have over five divisors (1,2,4,7,14,28).

What is the value of the smallest triangular number to have
over one hundred divisors? ... over two hundred divisors?

Based on a problem from Project Euler.

 No Solution Yet Submitted by Ady TZIDON No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
 By OEIS Comment 2 of 2 |
Not being a programmer I first checked this:

https://oeis.org/A063440

the number of divisors of each triangular number
you can easily scan to find the 384th triangular number has 112 factors and 2015th has 240.
(I thought the second interesting because it is the current year.)
but searching manually was a bit tough so I found the sequence of record breakers:

https://oeis.org/A101755

The last number given is the 281690531199th triangular number. I just checked and it has 387072 divisors.

 Posted by Jer on 2015-12-11 13:22:25

 Search: Search body:
Forums (0)
Random Problem
Site Statistics
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox: