Riesel Primes k*2^n-1, k<300 [Was "k=1"]

[Harvey563]

91 is completed from 210000 to 300000, & prime for 245989!

Harvey563

[JCS]

Number 91 on the top 5000 is now 9*2^828709-1, which was proven prime earlier today!

The k=9 search had been primeless for 6 months.

Other recent finds:
129*2^292573-1
129*2^310619-1
129*2^314188-1
129*2^331384-1

[Kosmaj]

Congrats on a big, top-100 prime!

[Keller]

k=231 checked through n=310000 and is prime for
231*2^205017-1
231*2^224297-1
231*2^248359-1

Tests on 237 and 241 going on ...

EDIT: I stop 231 at n=310k

EDIT2: Attached is the sieve file with the numbers not tested yet to n=500k for k=231

[Kosmaj]

Recently found primes and achieved limits are given below.

k=55: 397941 [400000]
k=71: 735802 prover's code L97 [736000]
k=79: 369535 [370000]
k=89: 369628 [380000]

[Kosmaj]

Is anybody interested in working on k=231 using pre-sieved values kindly provided by Keller above? If so, please announce your intentions in this thread. And please report primes (if any) by including "15k Search" in your prover's code.

[lsoule]

I'll take up the k=231 values and report back.
(looks like n goes up to 400k and not 500k.
I'll finish LLR up to 400k and sieve if it's still promising).

[lsoule]

Found a prime with 231:

k=231: 345183 [complete to 318k]

[Thomas11]

Seems as if no one is currently looking at k=75 (formerly tested by keller up to n=250000).
So, I'll take it a bit higher. Please let me know, if someone else has already choosen that k.

-- Thomas11

By the way: k=29 is tested through n=1.2M now!

[lsoule]

231*2^369583-1 is prime

231 is now complete to 400k and continuing.

-Larry

[robert44444uk]

Here is a note from Chris Caldwell's list:

220a 15*2^568780-1 171222 L52 2005

That is my second big prime from k=15 and my largest yet!

Regards

Robert Smith