iLWN project blog

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February 7, 2022 · MDPN
Tested 5.0% of all 23-digit numbers

On the 361st day since the start of the search among 23-digit numbers, the project passed the 5.0% mark of all candidates to be tested in this range! Twelve cores of two Intel Core i5-10400 processors are currently working on its testing. The sifting efficiency of Lychrel numbers is growing little by little and therefore the search speed is gradually increasing.

The total CPU time spent on testing 5.010% of the range counts to 380,736,757 seconds (105,760 hours or 4,406.7 days). A total of 55,288,404,752,640 numbers were checked, of which 52,992,885,039,828 (~95.85%) turned out to be Lychrel numbers. 19,254,087,329 delayed palindromes were saved in the database (steps from 50 to 289). The size of the database (separately for 23-digit numbers) reached 54.8 GiB.

Among the 23-digit numbers, 13 smallest delayed palindromes have been found so far: 9 of them are still considered as candidates (steps 237, 241, 242, 243, 245, 248, 262, 288 and 289), and 4 of them are reliably smallest numbers (steps 246, 247, 286 and 287). The longest known resulting palindrome in this range contains 142 digits, here are the first 20: 66343434455441881783.

Thus, checking the 23-digit range has been going on for almost a whole year (only four days are left until a full year)! Each day, an average of approximately 153.15 billion candidates were tested (or 0.01388% of all candidates in the range). The average total testing speed is 1.77 million candidates per second.

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February 3, 2022
The very first letters!

Hello everyone! Hooray, it finally happened! This is the very first diary entry written in English! And while all other (older) entries are still untranslated, from now on I will be updating both English and Russian pages every time a new post is added. So at least these untranslated entries will stop piling up. And time to time I will be translating older ones.

So, hello again and welcome to the blog!

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January 28, 2022
The blog, the diary, and the articles

I have not written a word here for a very long time (except for the posts moved to the blog from the events page). And it seems to me that the reason is that the format of the new blog, which I thought would be better, turned out to be completely inconvenient for me. And so, I decided to change back everything as it was before.

The blog will be again a project diary where I will periodically publish short posts about everything. And the articles will be moved to a separate page (the link to it is placed at the top, immediately below the title). The «Interesting Facts» section will be completely removed, all interesting information will now be located at the home pages of the relevant projects, and more voluminous facts will become normal articles.

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This is not the very beginning of the diary. And I've got many more entries! But I will move them back here a little later. Here is the old diary of the MDPN project (the page is in Russian), which was previously used as both a newsfeed and a blog. Also, you can always try to Google-translate this page from Russian.