I check what I did a long time ago.
I needed only primes under 10^6.
The 26th sqube is <removed by moderator>.
Hope this could help you.
Problem 200
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As your posts will be visible to the general public you are requested to be thoughtful in not posting anything that might explicitly give away how to solve a particular problem.
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Don't start begging others to give partial answers to problems
Don't ask for hints how to solve a problem
Don't start a new topic for a problem if there already exists one
See also the topics:
Don't post any spoilers
Comments, questions and clarifications about PE problems.
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h_anand
- Posts: 14
- Joined: Wed May 27, 2015 1:45 am
Re: Problem 200
Could anyone post a number that ends with either 1 or 3 or 7 or 9 (i.e., one of those numbers is in its units place) that is prime-proof? It does not have to be a sqube let alone one that contains 200.
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philiplu
- Posts: 92
- Joined: Wed Aug 02, 2017 8:51 pm
- Location: Redmond, WA, USA
Re: Problem 200
If you've solved the problem, take a look at my post from 15 Jan 2018. I ran through the first 100,000 prime-proof 200-squbes, and found 6 that ended in 1, 3, 7, or 9 (3 ended with a 7, 1 each of the other 3 units digits). The first of those was the 10,701st prime-proof 200-sqube, 884352220050857. You could easily modify my code to just look for prime-proof numbers that aren't divisible by 2 or 5.h_anand wrote: Wed May 02, 2018 11:09 pm Could anyone post a number that ends with either 1 or 3 or 7 or 9 (i.e., one of those numbers is in its units place) that is prime-proof? It does not have to be a sqube let alone one that contains 200.
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Zkid
- Posts: 4
- Joined: Wed Apr 04, 2012 12:09 am
Re: Problem 200
212159h_anand wrote: Wed May 02, 2018 11:09 pm
Could anyone post a number that ends with either 1 or 3 or 7 or 9 (i.e., one of those numbers is in its units place) that is prime-proof? It does not have to be a sqube let alone one that contains 200.
