[seqfan] Re: The two square composite sequence.

[Robert G. Wilson v]

  4,  81,  77
  9, 100,  91
 25, 144, 119
 36, 169, 133
  1, 144, 143
 64, 225, 161
  9, 196, 187
121, 324, 203

But also:
  1,  16,  15
  4,  25,  21
  9,  64,  55
 16,  25,   9
 25,  64,  39
 36, 121,  85
 49,  64,  15
 64, 121,  57
 81, 196, 115
100, 121,  21
121, 324, 203 
144, 169,  25
169, 256,  87
196, 289,  93
225, 484, 259
256, 289,  33
289, 324,  35
324, 529, 205
361, 400,  39
400, 529, 129
etc.

Sincerely yours, Bob.

-----Original Message-----
From: SeqFan [mailto:seqfan-bounces at list.seqfan.eu] On Behalf Of DAN_CYN_J
Sent: Sunday, September 01, 2013 5:10 PM
To: Sequence Fanatics Discussion list
Subject: [seqfan] The two square composite sequence.



The two squares associated with each semi-prime composite. 

The rules for the simi-prime composite is no composite will be a 0(mod 3 or
5) Each of it's two factors will be of equal length or 1 digit less like
7*11 =77 is the first composite in the 3rd index of the sequence. The two
previous index are just the two squares that is the solution to the
composites two factors. 
So every third term is a composite and the two previous terms are it's
associated squares as solutions. 
Which is the solution to x^2 - c = y^2 where c = a semi-prime composite and
is known as the Fermat factoring method. 


The sequence begins -- 

4,81,77,9,100,91,25,144,119,36,169,133,1,144,143,64,225,161,9,196,187,121,32
4,203... 

Dan 

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