The Cunningham Project is a collaborative effort started in 1925 to factor numbers of the form bn ± 1 for b = 2, 3, 5, 6, 7, 10, 11, 12 and large n. The project is named after Allan Joseph Champneys Cunningham, who published the first version of the table together with Herbert J. Woodall. There are three printed versions of the table, the most recent published in 2002, as well as an online version. The current limits of the exponents are: Factors of Cunningham number Two types of factors can be derived from a Cunningham number without having to use a factorisation algorithm: algebraic factors, which depend on the exponent, and Aurifeuillian factors, which depend on both the base and the exponent. Algebraic factors From elementary algebra, for all k, and for odd k. In addition, b2n − 1 = (bn − 1)(bn + 1). Thus, when m divides n, bm − 1 and bm + 1 are factors of bn − 1 if the quotient of n over m is even; only the first number is a factor if the quotient is odd. bm + 1 is a factor of bn − 1, if m divides n and the quotient is odd. In fact, and Aurifeuillian factors When the number is of a particular form (the exact expression varies with the base), Aurifeuillian factorization may be used, which gives a product of two or three numbers. The following equations give Aurifeuillian factors for the Cunningham project bases as a product of F, L and M: Let b = s2 × k with squarefree k, if one of the conditions holds, then have Aurifeuillian factorization. (i) and (ii) and Other factors Once the algebraic and Aurifeuillian factors are removed, the other factors of bn ± 1 are always of the form 2kn + 1, since they are all factors of . When n is prime, both algebraic and Aurifeuillian factors are not possible, except the trivial factors (b − 1 for bn − 1 and b + 1 for bn + 1). For Mersenne numbers, the trivial factors are not possible for prime n, so all factors are of the form 2kn + 1. In general, all factors of (bn − 1)&hairsp;/(b − 1) are of the form 2kn + 1, where b ≥ 2 and n is prime, except when n divides b − 1, in which case