Timeline for Prove that no 5 digit EXTREME PRIMES exist.
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17 events
| when toggle format | what | by | license | comment | |
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| Nov 11, 2021 at 9:19 | comment | added | Shieru Asakoto | @ScuffedNewton 1373 IS left-truncatable. I assume that you meant 1373 is not RIGHT-truncatable because 1 obviously isn't | |
| May 27, 2020 at 14:49 | audit | Reopen votes | |||
| May 27, 2020 at 14:53 | |||||
| May 20, 2020 at 20:06 | vote | accept | Scuffed Newton | ||
| May 16, 2020 at 9:59 | audit | Close votes | |||
| May 16, 2020 at 11:24 | |||||
| Apr 27, 2020 at 21:55 | answer | added | Barry Cipra | timeline score: 5 | |
| Apr 27, 2020 at 18:44 | comment | added | Scuffed Newton | @Peter, there are quite a few, I know there are no 5 digits, the proof lends itself to say 4 is the max. All 2 digit primes are extreme according to the definition, and one digit primes can't be extreme. Here are all the 3 and 4 digits: 113 131 137 173 179 197 311 313 317 373 379 419 431 479 613 617 619 673 719 797 971, 1373, 3137, 3797, 6131, 6173, 6197, 9719 | |
| Apr 27, 2020 at 18:35 | comment | added | Barry Cipra | @ScuffedNewton, good point. I stand corrected. Sorry, I should have compared the definitions more closely. | |
| Apr 27, 2020 at 18:33 | comment | added | Scuffed Newton | @ Barry Cipra, so for example, 1373 is right trunctable but not left, but is extreme. 373 is right truncutable, left trunctuable, and extreme. Some numbers can be left and right truncutable but not extreme. | |
| Apr 27, 2020 at 18:29 | comment | added | Scuffed Newton | @ Barry Cipra, that link you attached says there is a limited amount of right/left truncutable primes. Also They are not necessarily intersections as the digits need not be prime, hence the first and last digits can be composite,but must be prime if they are to be truncutable. Another thing is that if we take the number 1373, no trunctuable condition requires 37 to be prime, but the extreme prime does. While some terms are the same, the extreme primes include and exclude some other terms due to the above points. | |
| Apr 27, 2020 at 17:57 | comment | added | Peter | With backtracking, we can probably find all such primes. I do not think that the number of such primes exceeds $10$ a lot, if this is reached at all. | |
| Apr 27, 2020 at 17:46 | comment | added | Barry Cipra | I should add, it might be possible to prove the result you're after without making use of what's known about truncatable primes. So I don't mean to suggest that your notion of "extreme" prime is not worth pursuing. It's a nice idea, in fact. Kudos for thinking of it. | |
| Apr 27, 2020 at 17:42 | comment | added | Barry Cipra | @ScuffedNewton, you're quite right that your "extreme" primes are not literally the same as "truncatable" primes, but they are a subset of the intersection of the left- and right-truncatable primes, and given that those sets are both finite, so is the set of extreme primes. | |
| Apr 27, 2020 at 17:24 | comment | added | Scuffed Newton | People are referring to truncutable primes. They are not the same. Such number from the question would need to be right truncutable, left tructutable, and have primes in the middle of the digits. Not sure why these questions are related? If the proofs are mathematically similar I would understand, is this the case? | |
| Apr 27, 2020 at 17:21 | comment | added | David G. Stork | Also: math.stackexchange.com/questions/3363782/… | |
| Apr 27, 2020 at 17:18 | comment | added | Barry Cipra | This sounds closely related to "truncatable" primes. See mathworld.wolfram.com/TruncatablePrime.html for example. | |
| Apr 27, 2020 at 17:09 | history | edited | Derek Allums | CC BY-SA 4.0 |
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| Apr 27, 2020 at 16:51 | history | asked | Scuffed Newton | CC BY-SA 4.0 |