20200214, 10:50  #1 
Mar 2018
1017_{8} Posts 
sum of two positive cubes congruent to 1 mod Mersenne prime
344 and 559 are multiple of 43 and congruent to 1 mod a Mersenne prime
344 is infact congruent to 1 mod 7 (the greatest factor is 7) (3441)=7*7*7 (the greatest factor is 7) 559 is congruent to 1 mod 31 (the greatest factor is 31) (558=...*31) 344 and 559 are sum of two positive cubes are there other number k that are multiple of 43, sum of two positive cubes and such that the greatest factor of (k1) is a Mersenne prime? Last fiddled with by enzocreti on 20200214 at 10:51 
20200214, 12:23  #2  
Nov 2016
2820_{10} Posts 
Quote:


20200214, 12:36  #3 
Mar 2018
527_{10} Posts 
....
it is not multiple of 43
559 is multiple of 43 and congruent to 1 mod 31 
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