2006-05-03, 15:24 #1 Kosmaj     Nov 2003 2·1,811 Posts 17*2^n-1 k=17 has been reported as continuously tested to n=205,000 but there are 5 more primes found for larger exponents [the largest for n=601158]. With respect to reported n_max, k=17 is by far the largest "hole" in the k<300 group. The intention of this project is to extend the range of tested and reported exponents and to find new primes. k=17, although not a multiple of 3, is a very high-weight k and the probability of new primes for large n's is high. There is also a limited possibility of new primes for n<600k if some ranges were not checked, but there is no way to know. Since about 3 weeks ago Templus has been sieving k=17 for n in the 205k - 2M range. The first block, n<300k sieved to 850bn is ready for testing. Please consider testing a file or two if you have an idle machine. Thank you. Found primes 17*2^605394-1 (182243 digits) by segmtfault on Sep 19, 2006 17*2^2721830-1 (819354 digits) by unconnected on Oct 17, 2010 17*2^2946584-1 (887012 digits) by pepi37 on May 20, 2013 Status Code:  205,000-2,695,000 RPS - Complete (1 new prime) 2,695,000-2,800,000 unconnected - Complete (17*2^2721830-1 is prime!) 2,800,000-2,840,000 Kosmaj - Complete 2,840,000-2,900,000 unconnected - Complete 2,900,000-2,916,000 RPS - Complete 2,916,000-2,930,000 Kosmaj - Complete 2,930,000-3,000,000 pepi37 - Complete (17*2^2946584-1 is prime!) 3,000,000-3,010,000 Kosmaj - Complete 3,010,000-3,140,000 unconnected - Complete 3,140,000-3,150,000 pepi37 - Complete 3,150,000-3,250,000 unconnected - Complete 3,250,000-3,270,000 Kosmaj - Complete 3,270,000-3,320,000 unconnected - Complete 3,320,000-3,400,000 pepi37 - Complete 3,400,000-3,420,000 SectorX - Complete 3,420,000-3,450,000 Carlos - Complete 3,450,000-3,470,000 SectorX - Complete 3,470,000-3,490,000 Carlos - Complete 3,490,000-3,520,000 SectorX - Complete 3,520,000-3.550,000 kracker - Complete 3,550,000-3,570,000 SectorX - Complete 3,570,000-3,640,000 unconnected - Complete 3,640,000-4,000,000 Thomas11 - Complete 4,000,000-5,000,000 Batalov - Complete (17*2^4107544-1 is prime) Available Files Including all candidates in the 3-4M range, including already tested ones. Please help yourself by extracting the range you want to test. Extensively sieved by Psieve (latest update of August 19, 2013) k17_3M.zip (39353 candidates) FFT length of all tests: 192k. Last fiddled with by Batalov on 2015-07-12 at 15:59 Reason: 4,000,000-5,000,000 - Complete