Example is slightly faked 

When testing N=84923 one actully find first b-smooth z=436, z^2 mod N = 20250, which is 2*3^4*5^3.

Another important fact is that, we find in this example z=505 (less than "first" 513), is square 505^2 mod N = 256, which is 2^8. So whole procedure is somehow useless.

Maybe slightly better number N could be find to better ilustrate its application of Dixon's method.

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