The Cunningham project is described in the following excerpt from a sci.math posting by Bob Silverman, who has contributed many of the factorizations. In 1925 Lt.-Col. Alan J.C. Cunningham and H.J. Woodall gathered together all that was known about the primality and factorization of such numbers and published a small book of tables. "These tables collected from scattered sources the known prime factors for the bases 2 and 10 and also presented the authors' results of thirty years' work with these and the other bases" (see [1]) Since 1925 many people have worked on filling in these tables. It is likely that this project is the longest, ongoing computational project in history. D.H. Lehmer, a well known mathematician who passed away in 1991 was for many years a leader of these efforts. Professor Lehmer was a mathematician who was at the forefront of computing as modern electronic computers became a reality. He was also known as the inventor of some ingenious pre-electronic computing devices specifically designed for factoring numbers. These devices are currently in storage at the Computer Museum in Boston. For a history of this project I suggest you obtain a copy of: [1]: J. Brillhart, D.H. Lehmer, J. Selfridge, S.S. Wagstaff Jr., & B. Tuckerman Contemporary Mathematics vol 22, "Factorizations of b^n +/-1, b = 2,3,5,6,7,10,11,12 up to high powers", published by the American Math. Society 1983, 2nd Edition 1988