20230513, 02:39  #1 
Nov 2020
3·5 Posts 
Primes of the form 2401*2^n+1
I'm planning on searching k=2401 up to 3 million. I have a feeling that this base is slightly lucky due to 2401 = 7*7*7*7.

20230513, 03:17  #2 
Nov 2020
3·5 Posts 
I realized that PrimeGrid is already doing all the k's from 1 to 10000 so k=2401 is already taken. Maybe I'll do k = 1234321 instead?
Last fiddled with by YaoPlaysMC on 20230513 at 03:23 
20230513, 16:26  #3 
"Norman Luhn"
Jan 2007
Germany
2×3^{2}×43 Posts 
For open k's,you can take a look here
https://pzktupel.de/Primetables/TableProthTOP10KK.php Line 3446 is listed a k=2401. This top10000 starts with numbers >308000 digits. Last fiddled with by Cybertronic on 20230513 at 16:28 
20230702, 03:22  #4  
Random Account
Aug 2009
Oceanus Procellarum
5×607 Posts 
Quote:


20230708, 12:34  #5 
Dec 2022
2×3×7×13 Posts 
Of course all the specific numbers on the list have been tested and shown prime. An 'open' range is one that has not been tested, and PrimeGrid is indeed testing all k < 10,000 , and recording the primes found, so it would likely be inadvisable to search there.

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