Latest Factoring Results (c) February 4, 2024, by James Pate Williams, Jr.

I am testing two factoring algorithms: Pollard-Shor-Williams’s method, a home-grown version of the venerable Pollard rho algorithm and Pollard’s factoring with cubic integers. The second recipe is from “The Development of the Number Field Sieve” edited by Arjen K. Lenstra and Hendrik W. Lenstra, Jr. I use the 20-digit test number, 2 ^ 66 + 2 = 73786976294838206466. My method is very fast with this number as shown below:

2^66+2
73786976294838206466 20
Pseudo-Random Number Generator Seed = 1
Number of Tasks = 1
2 p 1
3 p 1
11 p 2
131 p 3
2731 p 4
409891 p 6
7623851 p 7
Elapsed hrs:min:sec.MS = 00:00:00.652
Function Evaluations = 1995

The Pollard factoring with cubic integers takes a long time but is capable of factoring much larger numbers. The results of the full factorization of my test number are:

== Data Menu ==
1 Simple Number
2 Fibonacci Sequence Number
3 Lucas Sequence Number
4 Exit
Enter option (1 – 4): 1
Enter a number to be factored: 2^66+2
Enter a random number generator seed: 1
== Factoring Menu ==
1 Lenstra’s ECM
2 Lenstra’s Pollard-Rho
3 Pollard’s Factoring with Cubic Integers
Option (1 – 3): 3
73786976294838206466

Enter a lower bound : -50000
Enter a upper bound : +50000
Enter b lower bound : +1
Enter b upper bound : +50000
Enter maximum kernels : 1024
Enter algebraic prime count: 300
Enter rational prime count: 300
Enter lo large prime bound: 10000
Enter hi large prime bound: 11000
Numbers sieved = 452239293
Successes 0 gcd(a, b) is 1 = 274929004
Successes 1 rational smooth a + b * r = 181838258
Successes 2 long long smooth = 68959
Successes 3 kernels tested = 535
2 p # digits 1
3 p # digits 1
11 p # digits 2
131 p # digits 3
2731 p # digits 4
409891 p # digits 6
7623851 p # digits 7
Runtime (s) = 36383.696000

It took over ten hours to fully factor, 2 ^ 66 + 2. I am currently attempting to factor the Thirteenth Fermat number which is 2 ^ (2 ^ 13) + 1 = 2 ^ 8192 + 1. The number has 2,467 decimal digits. I am using 399 algebraic prime numbers, 600 rational prime numbers, and 316 “large prime numbers” (primes between 12,000 and 15,000). I have to find the kernels of a 1316 by 1315 matrix. I am trying the factorization using a maximum of 8192 kernels. I suspect this computation will take about a week on my desktop workstation. There is no guarantee that I will find a non-trivial factor of 2 * (2731 ^ 3) + 2.

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Author: jamespatewilliamsjr

My whole legal name is James Pate Williams, Jr. I was born in LaGrange, Georgia approximately 70 years ago. I barely graduated from LaGrange High School with low marks in June 1971. Later in June 1979, I graduated from LaGrange College with a Bachelor of Arts in Chemistry with a little over a 3 out 4 Grade Point Average (GPA). In the Spring Quarter of 1978, I taught myself how to program a Texas Instruments desktop programmable calculator and in the Summer Quarter of 1978 I taught myself Dayton BASIC (Beginner's All-purpose Symbolic Instruction Code) on LaGrange College's Data General Eclipse minicomputer. I took courses in BASIC in the Fall Quarter of 1978 and FORTRAN IV (Formula Translator IV) in the Winter Quarter of 1979. Professor Kenneth Cooper, a genius poly-scientist taught me a course in the Intel 8085 microprocessor architecture and assembly and machine language. We would hand assemble our programs and insert the resulting machine code into our crude wooden box computer which was designed and built by Professor Cooper. From 1990 to 1994 I earned a Bachelor of Science in Computer Science from LaGrange College. I had a 4 out of 4 GPA in the period 1990 to 1994. I took courses in C, COBOL, and Pascal during my BS work. After graduating from LaGrange College a second time in May 1994, I taught myself C++. In December 1995, I started using the Internet and taught myself client-server programming. I created a website in 1997 which had C and C# implementations of algorithms from the "Handbook of Applied Cryptography" by Alfred J. Menezes, et. al., and some other cryptography and number theory textbooks and treatises.

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