- Torbjörn Alm has found the largest known CPAP-6 (6 consecutive primes in
arithmetic progression) at 301 digits:
200605912613*700# + 2437704499910036551539466113407 + 0, 30, 60, 90, 120, 150
Congratulations to Torbjörn!
He used my program and got very lucky:
The expectation was 8 days but it took about 3 hours! (After a bug was fixed
but let's not talk about that)
The GMP library was used for prp testing.
All primes were proved with Tony Forbes' VFYPR.
Two weeks ago, the largest known CPAP-6 was a mere 97 digits as far as I know.
Until now, people have apparently only given cpu time to the first discovery
of a CPAP-k (no longer relevant since CPAP-11 is too hard), and then to
titanic CPAP's which are required by The Prime Pages:
Chris Caldwell has a big influence on what people search!
Jim Fougeron found an impressive titanic CPAP-5 last year and that is very
hard, while the CPAP-6 remained extremely easy until recently.
The problem is maybe that there has not been a CPAP-k record page including
k's with titanic primes out of reach.
Now I have made such a page and announce it in a separate post. I was about to
mail that post when I saw Torbjörns CPAP-6 and wanted to update the page
first. I admit that I might not have bothered with these CPAP searches if I
had not planned a page to put them on.
I hope primenumbers members are not tired of my record announcements here. It
seems Prime Curios! got tired long ago and only approved the first 3 of 9
k-tuplet records for different k:
Or maybe the editors are just busy with other things.
Jens Kruse Andersen