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.

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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

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