Monday, August 10, 2020

A look ahead (reprise)

A year ago today I charted the expected progress on my five-year indexing-the-Leyland-primes project. Having a few days ago finished interval #10, I anticipate intervals #11 to #13 to be done by September, and #14 by October, all thanks to Mark Rodenkirch's xyyxsieve and pfgw.

my current work sheet

As I am no longer burdened by my previous reliance on Mathematica 9, I may even update everything to macOS Catalina one of these days. A new iMac is also being considered (if I can trade in my old kernel-panic-plagued late-2015 one). After I've finished interval #14, I will have tabulated all Leyland primes up to 103013 digits. Interval #15 will start there and continue on to the end of interval #28, reaching 150000 digits:

15  L(40945,328) - L(41507,322)   6612071   105334 (5e9)  6  Aug 28 - Sep 30
16  L(41507,322) - L(222748,3)   13527824   217348 (5e9) 12  Sep  3 - Oct 10
17  L(222748,3)  - L(45405,286)  33460389   536426 (5e9) 30  Oct  9 - Nov 18
18  L(45405,286) - L(48694,317)  69041008  1087659 (8e9) 72  Jan 23 - Mar  1
19  L(48694,317) - L(44541,746)  43871809   690863 (8e9) 72  Feb 25 - Mar 27
20  L(44541,746) - L(49205,532)  45659518   723121 (8e9) 72  Mar 20 - Apr 29
21  L(49205,532) - L(49413,580)  18377349   287809 (e10) 24  Nov 16 - Dec 31
22  L(49413,580) - L(49878,755)  54608684   856451 (e10) 72  Apr 21 - Jun  9
23  L(49878,755) - L(144999,10)  11614904   182243 (e10) 18  Dec 19 - Jan 22
24  L(144999,10) - L(145999,10)   8050111   126465 (e10) 12  Dec 18 - Jan 24
25  L(145999,10) - L(146999,10)   8094919   127396 (e10) 12  Nov 13 - Dec 19
26  L(146999,10) - L(147999,10)   8139747   128441 (e10) 12  Nov  6 - Dec 16
27  L(147999,10) - L(148999,10)   8184494   128015 (e10) 12  Sep 27 - Nov  7
28  L(148999,10) - L(149999,10)   8229120   129812 (e10) 12  Aug 31 - Oct  9

The column after the interval is the number of Leyland numbers between the end-points of that interval, followed by how many of those remain after sieving to the subsequent quantity (in brackets). This is followed by the number of iMac-mini cores working on primality testing and the start and finish dates (~ added if in the future). Initially, in addition to intervals #15 and #16, I will be having a go at interval #28 in order to up my PRPTop production score.

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