20220523, 17:05  #2135 
Dec 2016
170_{8} Posts 
M36919 has a 180.968bit (55digit) factor: 2997347544642661833497896836795494793702018162645139063 (P1,B1=2000000000,B2=401927737170960)
That gets me to the top of the list of P1 factors for Mersenne numbers! And all thanks to the new version 30.8 of mprime. 
20220523, 17:12  #2136 
"James Heinrich"
May 2004
exNorthern Ontario
3,833 Posts 

20220523, 17:17  #2137 
Jun 2003
2^{2}×7×193 Posts 
Nice!

20220523, 18:15  #2138 
Jul 2003
Behind BB
787_{16} Posts 
Wow! Congrats!

20220523, 18:47  #2139  
Apr 2020
855_{10} Posts 
Quote:
This comes in at 10th place on the alltime P1 list, i.e. not restricted to Mersennes. You should drop Paul Zimmermann an email; his address is on the page I linked. 

20220523, 19:31  #2140  
"James Heinrich"
May 2004
exNorthern Ontario
3,833 Posts 
Quote:
Last fiddled with by James Heinrich on 20220523 at 19:31 

20220523, 20:35  #2141  
Bamboozled!
"𒉺𒌌𒇷𒆷𒀭"
May 2003
Down not across
2CE4_{16} Posts 
Quote:
Don't let that stop you from trying to find more factors though. 

20220523, 20:39  #2142  
"Serge"
Mar 2008
Phi(4,2^7658614+1)/2
3·3,313 Posts 
Quote:
Crosspost it in the "(Preying for) World Record P1" thread 

20220523, 20:43  #2143  
Bamboozled!
"𒉺𒌌𒇷𒆷𒀭"
May 2003
Down not across
2^{2}×13^{2}×17 Posts 
Quote:
Code:
pcl@thoth:~/Astro/Misc$ ecm 10000 GMPECM 7.0.4 [configured with GMP 6.2.1, enableasmredc] [ECM] (2^73631)/223 Input number is (2^73631)/223 (2215 digits) Using B1=10000, B2=1678960, polynomial x^1, sigma=0:17348063569600894463 Step 1 took 838ms Step 2 took 724ms ********** Factor found in step 2: 4816405503271 Found prime factor of 13 digits: 4816405503271 Composite cofactor ((2^73631)/223)/4816405503271 has 2202 digits ((2^73631)/223)/4816405503271 Input number is ((2^73631)/223)/4816405503271 (2202 digits) Using B1=10000, B2=1678960, polynomial x^1, sigma=0:17644336739200299761 Step 1 took 833ms ********** Factor found in step 1: 616318177 Found prime factor of 9 digits: 616318177 Composite cofactor (((2^73631)/223)/4816405503271)/616318177 has 2193 digits 

20220525, 02:20  #2144  
Feb 2017
Nowhere
3×1,993 Posts 
Quote:
This leads to a ludicrous proof of compositeness and factorization: The fact that 223 divides 2^7363  1 though 223 < 7363 proves that 7363 is composite. Factoring 223  1 or 222, we get the prime factors 2, 3, and 37. And 37 divides 7363, the quotient being 199. Curiously, the factor 4816405503271 divides the "primitive part" (2^7363  1)/(2^37  1)/(2^199  1) of 2^7363  1. The cofactor (2^7363  1)/(2^37  1)/(2^199  1)/4816405503271 is composite. Last fiddled with by Dr Sardonicus on 20220525 at 02:23 Reason: gifnix topsy 

20220528, 14:38  #2145  
Apr 2020
3^{2}×5×19 Posts 
Quote:


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