Generalized repunit (probable) prime search

[sweety439]

This thread is for finding the smallest generalized repunit (probable) prime for a fixed base b, I have searched them for all bases 2<=b<=1024 and -1024<=b<=-2, see the text files. Of course, I know that there is no generalized repunit prime in base b for some bases because of the algebra factors, all such bases are either perfect powers or of the form -4k^4. Besides, I have completed these ranges:

Positive bases:

b<=400 to n=50000.
401<=b<=512 to n=30000.
513<=b<=1024 to n=10000.

Negative bases:

b>=-400 to n=50000.
-512<=b<=-401 to n=30000.
-1024<=b<=-513 to n=8000.

Also, I extended these searches for some smaller base b with no (probable) prime found, for positive bases, I completed b=185 to n=66337, b=269 to n=63659 and b=281 to n=63421, and for negative bases, I completed b=-97 to n=59863, b=-103 to n=59509 and b=-113 to n=59021, all have still no (probable) prime found.

[JeppeSN]

You could submit this information to the OEIS entries which are A128164 and A084742, respectively. /JeppeSN

[sweety439]

Originally Posted by JeppeSN

You could submit this information to the OEIS entries which are A128164 and A084742, respectively. /JeppeSN

I do not have OEIS account and not decide to create.

[Citrix]

How did you extend these ranges? Is there a good sieve software and fast PRP software.
If you used PFGW - what setting did you use?

Thanks.

[GP2]

From OEIS A028491, Paul Bourdelais has discovered a new base-3 repunit (probable) prime:

(3^2215303 − 1) /2 is a PRP


The Lifchitz PRP Top page shows two other discoveries in January for bases −6 and −7:

(6^1313371 + 1) /7
(7^1178033 + 1) /8

[rudy235]

Originally Posted by GP2

From OEIS A028491, Paul Bourdelais has discovered a new base-3 repunit (probable) prime:

(3^2215303 − 1) /2 is a PRP

1'057,967 digits

[lalera]

hi,
reserving R[6]
from n=608100 to 1000000

[lalera]

Originally Posted by lalera

hi,
reserving R[6]
from n=608100 to 1000000

range done. no prp found