Tool to test Lychrel numbers. A Lychrel number is a natural integer which does not end the iterative process: while a number is not a palindrome, add the number to its mirror (created by reversing the order of its digits) in order to obtain a new number.

dCode is free and its tools are a valuable help in games, maths, geocaching, puzzles and problems to solve every day! A suggestion ? a feedback ? a bug ? an idea ? Write to dCode!

> [News]: Discover the next version of dCode Lychrel Number!

Tool to test Lychrel numbers. A Lychrel number is a natural integer which does not end the iterative process: while a number is not a palindrome, add the number to its mirror (created by reversing the order of its digits) in order to obtain a new number.

Answers to Questions

How to calculate iterations of a Lychrel number?

Add a number to the value of its mirror (the order of its digits are reversed) to obtain a new number. If this number is a new palindrome, stop, else start again with this number.

Example: 360 + 063 = 423 423 + 324 = 747

What are the Lychrel numbers?

Lychrel numbers never creates such a palindrome. A conjecture suppose that there are an infinite number of Lychrel numbers.

Here are the first conjectured Lychrel numbers (below 1000) : 196, 295, 394, 493, 592, 689, 691, 788, 790, 879, 887, 978, 986 (link)

What is the smallest Lychrel number?

The smallest Lychrel number Lychrel is 196. Yet, nobody has been able to prove that it never forms a palindrome.

What is the the most delayed Lychrel number?

A number is delayed when there a multiple steps before becoming a palindrome. The most delayed known is 1186060307891929990 with 261 iterations.

Source code

dCode retains ownership of the source code of the script Lychrel Number online. Except explicit open source licence (indicated Creative Commons / free), any algorithm, applet, snippet, software (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any function (convert, solve, decrypt, encrypt, decipher, cipher, decode, code, translate) written in any informatic langauge (PHP, Java, C#, Python, Javascript, Matlab, etc.) which dCode owns rights will not be given for free. To download the online Lychrel Number script for offline use on PC, iPhone or Android, ask for price quote on contact page !

Questions / Comments

> [News]: Discover the next version of dCode Lychrel Number!

> [

News]: Discover the next version of dCode Lychrel Number!