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 LaurV 2021-08-08 08:48

Aren't mersenne prime palindromes themselves? :razz:

 paulunderwood 2021-08-08 09:04

[QUOTE=LaurV;585155]Aren't mersenne prime palindromes themselves? :razz:[/QUOTE]

I base 2 they are. In fact any n>1 is a palindrome in base n+1 and in base n-1 :grin:

 sweety439 2021-08-08 14:07

[QUOTE=LaurV;585155]Aren't mersenne prime palindromes themselves? :razz:[/QUOTE]

All primes p not in [URL="https://oeis.org/A016038"]https://oeis.org/A016038[/URL] are palindromes in some base < p-1

 paulunderwood 2021-09-11 08:21

Congrats to Serge and Ryan for the two smallest known Mega primes, prove with CHG at 28.7% factored of N+1

[URL="https://primes.utm.edu/primes/page.php?id=132705"]10^999999 - 1022306*10^287000 - 1[/URL]

[URL="https://primes.utm.edu/primes/page.php?id=132704"]10^999999 - 1087604*10^287000 - 1[/URL]

:banana: :banana:

 Batalov 2021-09-11 10:44

[QUOTE=paulunderwood;587681]Congrats to Serge and Ryan for the two smallest known Mega primes, prove with CHG at 28.7% factored of N+1
[/QUOTE]
Two [I]largest [/I]known [I]less-than-Mega primes[/I], actually.
(The second one was found before search was called off, an incidental finding. :rolleyes: )

[CODE]...
10^999999+308267*10^292000+1 P 1000000 Batalov 02/2021
10^999999+593499 PRP 1000000 Peter Kaiser 02/2013
10^999999 C 1000000 --- a composite, smallest million-digit number
10^999999-172473 PRP 999999 Patrick De Geest 12/2016
10^999999-1022306*10^287000-1 P 999999 Propper,Batalov 09/2021
10^999999-1087604*10^287000-1 P 999999 Propper,Batalov 09/2021
...[/CODE]

 rudy235 2021-09-11 16:50

[QUOTE=LaurV;585155]Aren't mersenne prime palindromes themselves? :razz:[/QUOTE]

Of course all repunits are “palindromes” per se, but in practical terms when a prime is a Mersenne, a Generalized Mersenne ( to other bases ), repunits, generalized repunits, they are not counted as palindromes in the database of “The primePages”

 paulunderwood 2021-09-12 17:20

Congrats to Marc Wiseler and PrimeGrid for the "321" prime [URL="https://primes.utm.edu/primes/page.php?id=132678"]3*2^17748034-1[/URL] (5,342,692 decimal digits) ranked as the 18th largest known prime.

:banana: :banana: :banana:

 diep 2021-09-12 17:22

[QUOTE=paulunderwood;587767]Congrats to Marc Wiseler and PrimeGrid for the "321" prime [URL="https://primes.utm.edu/primes/page.php?id=132678"]3*2^17748034-1[/URL] (5,342,692 decimal digits) ranked as the 18th largest known prime.

:banana: :banana: :banana:[/QUOTE]

Big congrats!!!!!

 Batalov 2021-09-14 20:08

Another Riesel "other" number is [I]coming soon[/I].

It is a palindrome, chock full of "9"s (with a few others) and is neatly 1,234,567 decimal digits long

 paulunderwood 2021-09-14 21:01

[QUOTE=Batalov;587870]Another Riesel "other" number is [I]coming soon[/I].

It is a palindrome, chock full of "9"s (with a few others) and is neatly 1,234,567 decimal digits long[/QUOTE]

I am looking forward to its revelation. The largest palindrome before this one had 490,001 digits. So 1,234,567 digits is quite amazing considering its crunching is done with generic modular reduction.

 sweety439 2021-09-15 07:15

[QUOTE=paulunderwood;587879]I am looking forward to its revelation. The largest palindrome before this one had 490,001 digits. So 1,234,567 digits is quite amazing considering its crunching is done with generic modular reduction.[/QUOTE]

[URL="https://primes.utm.edu/primes/status.php"]https://primes.utm.edu/primes/status.php[/URL]

id 132704 and 132705 are palindromes.

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