[seqfan] Re: The two square composite sequence,

DAN_CYN_J dan_cyn_j at comcast.net
Tue Sep 3 01:35:02 CEST 2013


Hi again seqfans, 
  
 I should also have stated in the rules that these composites 
should only be odd thus eliminating prime (2). 
One seqfan member sent a list with an (8) as one of the composites. 
   
The reason for these eliminations is the whole sequence will be 
convoluted with unnecessary terms. 
As in the case of elimination 0(mod 3 or 5) , if you start with the 
additive sequence 7+4+2+4+2+4+6+2+6 then keep repeating 
+4+2+4+2+4+6+2+6... all primes and selected odd composites, 
no 0(mod 3 or 5) composites, will fall in this additive sequence. 
  
If anyone would like to add to this sequence just put the smallest square 
first followed by the larger square then the associated composite 
of the two squares. Therefore creating a composite every 3rd term. 
These composites are also limited to just two prime factors of equal 
length or the smaller factor at most one digit less then the largest factor. 
This is probably the closest definition of a semi-prime composite. 
  
4,81,77,9,100,91,25,144,119,36,169,133,1,144,143...   
  
TIA 
  
Dan    



More information about the SeqFan mailing list