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-   Riesel Prime Search (https://www.mersenneforum.org/forumdisplay.php?f=59)

 Batalov 2014-03-25 16:02

Found a couple small "EQ" (Eisenstein-Mersenne cofactors, OEIS [URL="http://oeis.org/A125743"]A125743[/URL]/[URL="http://oeis.org/A125744"]4[/URL]) (probable) primes:
(3^152809+3^76405+1)/7 is a 2-PRP!
(3^272141-3^136071+1)/7 is a 2-PRP!
(3^505823+3^252912+1)/7 is a 2-PRP! (241339 digits)
(3^1353449-3^676725+1)/7 is a 2-PRP! (645759 decimal digits) [B]Time: 10953.669 sec.[/B]

Notes:
1. The running time. With most tools you will get > 20000 sec. This is because of the implementation of FFT modulo 3[SUP]3p[/SUP]+1 with only final step done modulo N.
2. All of similar (composite or prime) numbers are 3-PRPs. Re-validating now with -b5, -b11.

 pepi37 2014-05-19 07:49

Small prime, but for me it is huge :)

[URL="http://primes.utm.edu/primes/page.php?id=117862"]Fifth in his class in the world[/URL] (currently) of course :))

94 followed but 466002 number nine :)

 Batalov 2014-10-02 21:16

The Riesel Problem: one less to go

A new elimination from the Riesel Problem is currently in the [URL="http://primes.utm.edu/primes/page.php?id=118583"]UTM queue[/URL] (into position 20!)

Congrats to PrimeGrid!

 Citrix 2014-10-06 05:05

[QUOTE=Batalov;384236]A new elimination from the Riesel Problem is currently in the [URL="http://primes.utm.edu/primes/page.php?id=118583"]UTM queue[/URL] (into position 20!)

Congrats to PrimeGrid![/QUOTE]

Another one!
502573*2^7181987 - 1 is prime!:smile:
Congrats to PrimeGrid.

 unconnected 2014-10-06 13:38

[URL]http://primes.utm.edu/primes/page.php?id=118597[/URL]
Congratulations to my teammate!

 pepi37 2015-04-30 22:07

99*10^303255-1 is prime! (303257 decimal digits, P = 33) Time : 2119.757 sec. :smile:

 Kosmaj 2015-05-01 05:51

Hi Pepi

Congrats, but it seems it's not enough for top 20 near-repdigits:
[URL="http://primes.utm.edu/top20/page.php?id=15"]http://primes.utm.edu/top20/page.php?id=15[/URL]

 pepi37 2015-05-01 09:23

[QUOTE=Kosmaj;401394]Hi Pepi

Congrats, but it seems it's not enough for top 20 near-repdigits:
[URL]http://primes.utm.edu/top20/page.php?id=15[/URL][/QUOTE]

I know that fact, but it is rare prime :)
Hunting is continued :)

 pepi37 2015-05-16 03:48

Last was not in Top 5000 , but this fellow is :)

92*10^544905-1 is prime! (544907 decimal digits, P = 5) Time : 7082.969 sec.

Reported and verified on Top 5000 :)

 paulunderwood 2015-05-16 04:33

[QUOTE=pepi37;402390]Last was not in Top 5000 , but this fellow is :)

92*10^544905-1 is prime! (544907 decimal digits, P = 5) Time : 7082.969 sec.

Reported and verified on Top 5000 :)[/QUOTE]

Congrats. That is a lot of nines in its decimal expansion :smile:

 pepi37 2015-05-16 04:35

[QUOTE=paulunderwood;402392]Congrats. That is a lot of nines in its decimal expansion :smile:[/QUOTE]

Yes, 544905 nines :)

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