PRPs that are composites - Page 6

rogue · 2011-09-12, 01:17

Quote:

Originally Posted by Batalov

44766250*3^7+1 = 97903788751 is a composite base 3 PRP (also base 5 PRP and base 15 PRP).

97903788751 = 221251 * 442501 = p(2p-1).

(Found as 1933902*15^4+1. 1933902*15^7+1 is prime.)

Thanks. I assume that was with 3.4.9. Is that correct?

Batalov · 2011-09-12, 02:40

Yes.

...but this is not a bug, or do you want to switch to another base automatically?

rogue · 2011-09-12, 12:31

Quote:

Originally Posted by Batalov

Yes.

...but this is not a bug, or do you want to switch to another base automatically?

It will not switch to another base because it didn't detect an error. As Max stated in an earlier post, use another base (such as 8 via -b8) and it should reduce, if not eliminate problems like this with base 3.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Near- and quasi-repunit PRPs	Batalov	And now for something completely different	10	2019-09-12 13:31
Very (large) PRPs?	PawnProver44	Information & Answers	95	2016-05-20 18:24
OEIS - (2^n-5)/3 - n odd - LLT-like algorithm for finding PRPs	T.Rex	Miscellaneous Math	10	2015-09-01 18:07
PRPs not prime	schickel	FactorDB	1	2015-08-03 02:50
Proven PRPs?	Random Poster	FactorDB	0	2012-07-24 10:53

2011-09-12, 02:40	#57
Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 2⁴·593 Posts	Yes. ...but this is not a bug, or do you want to switch to another base automatically?