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Proposed Release Schedule for New Problems

  • Problem 637 will be accessible in 6 hours, 2 minutes (Sunday, 23rd September 2018, 01:00 am)
  • Problem 638 is scheduled for Sunday, 7th October 2018, 04:00 am
  • Problem 639 is scheduled for Sunday, 21st October 2018, 07:00 am

Recent News

27 May 2018: Project Euler and the GDPR

As many of you will know, the law concerning any data held by European citizens: General Data Protection Regulation (GDPR), came into effect on 25 May 2018. Not only is the website hosted in Europe, but a large proportion of our membership also live within Europe, so this legislation affects us.

For some time now we have been reviewing and discussing our policies and practices to ensure that we would be compliant with the new legislation when it came into effect. If you are familiar with the GDPR, then you will know from our previous privacy policy that the main website,, was already compliant. This is due to a combination of having anonymous accounts (that is, we require no personal data which could be used to identify an individual), members having full control over any data they enter, and always providing a full and transparent disclosure of how we handle data. However, as a way to ensure that we communicate as clearly as possible how we operate it was felt by the team that the privacy policy should be updated to ensure greater clarity in all parts. For this reason, we ask all members to take the time to read and review the Privacy Policy.

Where we have made important changes, however, is with the Project Euler alternative forum:, which uses the latest release of the phpBB forum software. In order to operate with consistency across both websites we have made the decision to ensure anonymity there too. That is, we have removed all user email addresses from the database, there is neither a requirement nor an option to enter email addresses, and user IP addresses are no longer recorded. So it should be noted that all previous functionality relating to emails, such as notifications, are no longer available. As with the main website, if you have already created an account at the forum, then we would ask that you visit the website to read and review the privacy policy.

We hope that you are happy with the outcome of our review and continue to enjoy being a part of the Project Euler community.

18 February 2018: Changing Statistical Data View

It is now possible to change the statistical data shown on the Statistics pages from the default view of all registered members to active members only; that is, members who have solved a problem within the last 365 days.

It should also be noted that changing to the alternative view will create a cookie (name = statistics_show) to remember your choice. If you revert back to all registered members, then the cookie will be deleted. The Privacy Policy has been updated to reflect this change.

10 February 2018: New BBCode [Collapse]

A recent BBCode has been added to the forum: [collapse], allowing members to post blocks of text that can be expanded and collapsed. It works in the same way as the code block, except you can use any other formatted text within it, including TeX. For more information on the usage of this tag and the others, then please see:

It may be useful when you wish to post a lengthy section of text (for example, proofs or program output) which might otherwise interfere with the brevity of your post. Similarly if you wish to hide solutions/spoilers relating to extension questions posed by members on the current problem.

On the subject of spoilers, it has been noted on occasion that some members have posted comments like, "I used the same code to solve problem XXX" or "By changing your algorithm in the following way you can solve problem YYY". We understand that this has always been well meaning, but other members may not have solved that problem yet and would like to tackle it independently for themselves. So we would ask that members, when referring to other problems, hide the reference with the hide tag or the new collapse tag for longer replies; see link above for usage.

2 September 2017: Start of the new season

The new season will start Saturday, September 9th, 2017, 16:00 server time.

Last year it became challenging for the team to continue with the weekly publication scheme. Now that we have over 600 problems published, finding new and interesting problems is becoming increasingly difficult.

As long as we have a sufficient number of problems that are ready for publication then we are able to maintain a weekly release of new problems. However, we currently do not, so we have made a decision to reduce the release of new problems to one problem every two weeks. If we can re-establish enough ready-to-publish problems, then we will return to weekly publication.

As you are aware, many of the excellent problems that we have learned to enjoy have come about through the contributions of our members. If you have any interesting ideas for new problems, then please consider making a problem proposal. See Suggesting New Problems for more information on the process.

10 August 2017: Summer 2017 Website Update

A major rewrite of the main website back end has been taking place on my local machine for some time and on 10 August 2017 the updated scripts were uploaded. It is hoped that the changes made will provide a little more fluidity and robustness to the functionality of the website. Sadly, very little has been done in terms of cosmetics, so you are unlikely to notice much on the surface, but I can assure you that significant changes have been made to the way the website handles data.

With any update there is only so much testing that can be done locally before the changes are made to the production website. So it would be very helpful if the thread: Summer 2017 Website Update at the Project Euler forum is used to report any bugs that you might identify. I would ask for your patience if any bugs or issues come to light as I hope the necessary changes will benefit all of us in the long term.