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Welcome to p196.org!

This site is about a set of numbers that do not form a palindrome through the process of reversing and adding their digits. These numbers have become known as "Lychrel Numbers".

Lychrel Numbers and Palindromes For example, let's begin with the number 7,326...

If we reverse its digits and add it to the original number, we get 13,563. Like so:

7326 + 6237 = 13563

Since this new number is not a palindrome, we can continue the reverse and add process and it may become one:

7326 + 6237 = 13563
13563 + 36531 = 50094
50094 + 49005 = 99099 ---- A Palindrome

Most of the time only a few iterations (less than 10) are needed before the number becomes a palindrome. In the case of Lychrel Numbers, it is believed that they will never become palindromes, no matter how many iterations are performed on the number.

This page started as my experience with the first of those magical numbers...

But has since grown to include enough information, about other numbers, that I couldn't really call it "Nothing but 196" any longer. I have to admit that I find all of these numbers interesting. 196 just was the one that I started with. You can always jump straight to Lychrel Records, to see how many there are, and the status of some of the numbers other than 196. or you could go to the Files, Files, Files page if you just want to download some of them.

My Blackboard has the latest news and findings, including the most current state of the 196 quest. It also has questions and ideas from time to time, that just don't seem to fit anywhere else.

The Blackboard Archive is the place that all news stories move to, when the main Blackboard page gets cluttered. There is a ton of information that has made it's way to this page. It is a long but good page to read.

The Milestones gives a history of major milestones in the 196 quest.

Some of the lower Lychrel numbers have been tested out hundreds of millions of digits without becoming palindromes. Obviously, a standard calculator isn't of any value. The programs listed on the Software Comparisons page represent hundreds of hours of work by the authors and were all written specifically for this quest. none of it is "off the shelf" software. :-) These Lychrel Records would all be easily classified as world records by groups such as Guiness Book, if we were interested enough to submit them. Mostly we only do this for fun.

Although there is a lot of information on these pages that deal with mathematical ideas and thoughts, this is not a math site. The vast majority of these pages are written so that with minimal thought, the concepts and ideas should be clear to everyone. Some of the papers listed on the Math Solutions page are a bit more challenging. But even those should be understandable if you give them a bit of thought. I hope everyone finds something enjoyable in this site. A lot of people have spent a lot of time contributing to it. We are proud of what we have created.

Thanks for visiting!