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[QUOTE=sweety439;545220]Are there any searching for near- and quasi- repunit primes (primes of the form aaa...aaab, abbb...bbb, aaa...aaabc, abbb...bbbc, abccc...ccc, see thread [URL="https://mersenneforum.org/showthread.php?t=19717"]https://mersenneforum.org/showthread.php?t=19717[/URL]) in dozenal (duodecimal)?
There are a lot of such searching in decimal ([URL="https://stdkmd.net/nrr/#factortables_nr"]https://stdkmd.net/nrr/#factortables_nr[/URL] and [URL="https://stdkmd.net/nrr/prime/primedifficulty.txt"]https://stdkmd.net/nrr/prime/primedifficulty.txt[/URL]), and I finished this searching in dozenal up to n=1000 (decimal 1728)[/QUOTE] 5 out of the 6 largest known Mersenne Prime exponents are ended with 5 when written in the dozenal base. Also, I cannot find any 9s in all of them. Ӿ,ӾƐ3,855 12,531,515 17,476,435 20,Ӿ28041 21,Ӿ46,Ɛ85 23,7ӾƐ,125 |
I can do better: when written in base 2, [U][B]all[/B][/U] mersenne prime's exponents end in 1.
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[QUOTE=LaurV;558296]I can do better: when written in base 2, [U][B]all[/B][/U] mersenne prime's exponents end in 1.[/QUOTE]
All but the first... |
[QUOTE=tuckerkao;558291]5 out of the 6 largest known Mersenne Prime exponents are ended with 5 when written in the dozenal base. Also, I cannot find any 9s in all of them.
Ӿ,ӾƐ3,855 12,531,515 17,476,435 20,Ӿ28041 21,Ӿ46,Ɛ85 23,7ӾƐ,125[/QUOTE] In dozenal, no primes end with 9, since all numbers end with 0, 3, 6, 9 are divisible by 3 (see [URL="https://dozenal.fandom.com/wiki/Divisibility_rule"]Dozenal divisibility rule[/URL]) Also, these project is for the [B]near-repunit and quasi-repunit[/B] primes in dozenal, not for the Mersenne Prime exponents in dozenal. |
[URL="https://dozenal.fandom.com/wiki/Near-repdigit_prime"]status for dozenal near-repdigit primes[/URL]
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[QUOTE=sweety439;558303]In dozenal, no primes end with 9, since all numbers end with 0, 3, 6, 9 are divisible by 3 (see [URL="https://dozenal.fandom.com/wiki/Divisibility_rule"]Dozenal divisibility rule[/URL])
Also, these project is for the [B]near-repunit and quasi-repunit[/B] primes in dozenal, not for the Mersenne Prime exponents in dozenal.[/QUOTE] I was mentioning about no 9s for the entire numbers not only the ending units. For example 9 dozen 1 and 9 dozen 5 are both primes. [QUOTE=LaurV;558296]I can do better: when written in base 2, [U][B]all[/B][/U] mersenne prime's exponents end in 1.[/QUOTE] The 0 enders = even numbers, the 1 enders = odd numbers which sound very familiar to everyone. Base 4 will give more insights as whether the prime exponents turn out to be the 1 ender or the 3 ender. |
[QUOTE=tuckerkao;558310]I was mentioning about no 9s for the entire numbers not only the ending units.
For example 9 dozen 1 and 9 dozen 5 are both primes. The 0 enders = even numbers, the 1 enders = odd numbers which sound very familiar to everyone. Base 4 will give more insights as whether the prime exponents turn out to be the 1 ender or the 3 ender.[/QUOTE] Well, there is a list for all Mersenne primes and all Mersenne exponents in dozenal: [URL="https://dozenal.fandom.com/wiki/Mersenne_prime"]https://dozenal.fandom.com/wiki/Mersenne_prime[/URL] All Mersenne primes > 3 end with 7, and all Mersenne primes > 7 end with either 27 or X7 (27 and X7 are the only two-digit Mersenne primes). Also, Mersenne exponents end with E are fewer than Mersenne exponents end with 1, 5, or 7, since if p end with E and 2p+1 is also prime (e.g. p = E, 1E, 6E, XE), then Mp is divisible by 2p+1, thus composite. |
[QUOTE=Dr Sardonicus;558298]All but the first...[/QUOTE]
Yet, I did better than him! :razz: |
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[QUOTE=sweety439;558318]Well, there is a list for all Mersenne primes and all Mersenne exponents in dozenal: [URL="https://dozenal.fandom.com/wiki/Mersenne_prime"]https://dozenal.fandom.com/wiki/Mersenne_prime[/URL]
All Mersenne primes > 3 end with 7, and all Mersenne primes > 7 end with either 27 or X7 (27 and X7 are the only two-digit Mersenne primes). Also, Mersenne exponents end with E are fewer than Mersenne exponents end with 1, 5, or 7, since if p end with E and 2p+1 is also prime (e.g. p = E, 1E, 6E, XE), then Mp is divisible by 2p+1, thus composite.[/QUOTE] Thanks for the list, it seems like when the exponents end in dozenal 5, it has the slightly higher chance for being a Mersenne Prime. I have my list for the exponents in dozenal enders, Red for 1, Blue for 5, Pink for 7, Skyblue for Ɛ. |
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